Iranian forces have launched hundreds of drones and missiles in multiple waves across the Middle East, but without inflicting significant harm against American assets in the region, such as sinking a warship or destroying a base.
By contrast, American and Israeli strikes have already devastated regime targets in Iran. They have taken out the head of the regime, Ali Khamenei, as well as the army's chief of staff, General Abdol Rahim Mousavi, and defence minister General Aziz Nasirzadeh.
Iran latest: Three US service members killed
Then again, it is only day two of the war and the Islamic Revolutionary Guard Corps (IRGC) has pledged "severe, decisive and regret-inducing punishment".
Yet the more time that passes without this rhetoric becoming a reality, the greater the questions about whether Iran's most feared military forces still have the capability to locate, target and strike the US and Israeli warships and jets attacking them.
General Sir Richard Barrons, a former senior UK military officer, said a number of factors would likely be limiting Iran's options for manoeuvre, not least the loss of so many top leaders.
Any move to fire missiles would also expose the launch site to American and Israeli attacks from the air, meaning Iran's missile launchers would have "quite a short" life expectancy.
In addition, previous attacks by both the US and Israel against Iran over the past couple of years have already degraded its missile stockpiles, launchers and air defences to blunt the regime's ability to detect incoming enemy aircraft.
All of this could explain why so few US and Israeli military targets appear so far to have suffered much meaningful damage despite Iran firing hundreds of missiles and drones.
Though the full extent of any damage is unclear.
UK Defence Secretary, John Healey, warned that a wounded Iran still has the capacity to cause harm - just potentially in even more erratic ways with little regard for the impact on the millions of civilians who live across the Gulf.
"This regime is lashing out. It's lashing out in an increasingly indiscriminate and widespread way," he said, speaking to Sky News's Sunday Morning with Trevor Philips.
"And people will be really concerned that it's not just military targets, but civilian airports like Kuwait, hotels in Dubai and Bahrain are being hit."
Tourist hotspots in the crossfire
Countries so far impacted include Israel, Qatar, the United Arab Emirates, Bahrain, Kuwait, Jordan and Iraq, where a number of American bases are located.
Many of the munitions appear to have been intercepted, but falling debris can be deadly.
With so much metal flying around, civilian and tourist locations have been caught in the crossfire, including one of the world's busiest airports in Dubai, where all flights have been halted, and the entrance of a luxury hotel.
This would have been terrifying for those affected but these strikes appear to have done nothing to degrade the ability of the US and Israel to keep hitting Iran.
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A high-value target for the regime must surely be two American aircraft carrier strike groups, led by the USS Gerald R Ford and the USS Abraham Lincoln.
They're thought to be located south of Cyprus.
An attempt to hit these warships might explain why the UK says two Iranian missiles were fired in the direction of the Mediterranean island. Britain has bases on Cyprus but they are not thought to have been the focus of the attack.
General Barrons said an outmatched Iran on the battlefield might seek alternative ways to strike back such as by closing the Strait of Hormuz - a vital transit point for global oil and gas exports.
Disruption to this shipping lane would impact economies around the world - and it is already starting with tankers being targeted, including off the coast of Oman.
President Trump is gambling that Iran lacks the capability to resist his overwhelming firepower. And that may well be the case.
But it only takes one Iranian missile penetrating American air defences to alter that calculation or at least dramatically increase the cost to Washington of its war.
He took over from the regime's founding figurehead, Ayatollah Ruhollah Khomeini, when he died just over 10 years later, in June 1989.
Iran's supreme leader has the final say in all matters of state.
Therefore Khamenei's death, after almost 37 years in power, marks a major transition.
Iran latest: Ayatollah Khamenei killed
Which senior leaders have died?
In addition to Khamenei, several other senior officials were killed in US/Israeli airstrikes too.
They include Iran's army chief of staff, General Abdol Rahim Mousavi, and defence minister General Aziz Nasirzadeh.
Also killed was Major General Mohammad Pakpour, who took over as the Revolutionary Guard's top commander after Israel killed its last commander last June, and Ali Shamkhani, a top security adviser to Khamenei.
Iranian media said Khamenei's daughter, grandchild, son-in-law and daughter-in-law were killed as well.
The Israel Defence Forces also claimed it had killed Saleh Asadi, head of the Intelligence Directorate of the Khatam al Anbiya emergency command, Mohammad Shirazi, head of the military bureau, Hossein Jabal Amelian, head of SPND (Organisation of Defensive Innovation and Research) and Reza Mozaffari-Nia, a former head of SPND and former deputy defence minister.
What happens now?
A three-person temporary leadership council has been formed to govern the country, in line with Islamic Republic law.
It includes Iran's reformist president, Masoud Pezeshkian, and the hard-line head of the judiciary, Gholamhossein Mohseni Ejei.
There will also be a jurist, Alireza Arafi, who is a member of Iran's Guardian Council and head of the Basij, a volunteer paramilitary force.
Ali Larijani, Iran's head of security, said the council would be set up on Sunday.
"We had prepared for such moments and have plans in place for all scenarios, even for the time after the martyrdom of revered Imam Khamenei," said Mohammad Bagher Qalibaf, Iran's parliamentary speaker.
He added: "You'll see that after the leadership council is formed, the power and integrity of officials, defensive forces and the people will be beyond imagination."
Who chooses the new leader?
While the leadership council will govern in the interim, an 88-member panel called the Assembly of Experts will pick a new leader. Under Iranian law, that must happen as soon as possible.
The panel is made up of Shiite clerics elected every eight years and whose candidacies are approved by Iran's constitutional watchdog.
The Guardian Council is known for disqualifying candidates. It barred former Iranian president Hassan Rouhani from election to the Assembly of Experts in March 2024.
A relative moderate, he struck the JCPOA nuclear deal with world powers in 2015, from which the US, under Donald Trump, later withdrew.
Who could be the new supreme leader?
Under Iran's system of vilayat-e faqih - guardianship of the Islamic jurist - the supreme leader must be a senior leader with political and religious authority.
Khamenei's power was often wielded through close advisers. But it is unclear how many have survived, and he was never publicly recorded as naming a successor.
His son, Mojtaba Khamenei, a 56-year-old cleric, has been seen as a possible successor. He has never held government office, however.
That said, he has been described as a gatekeeper to his father.
He studied under religious conservatives in seminaries in the city of Qom, and is described as a hardliner with close ties to the Revolutionary Guard.
It had been thought that former president Ebrahim Raisi might seek the leadership, but he died in a helicopter crash in May 2024.
Regime change?
Donald Trump is urging Iranians to take the opportunity to overthrow the Islamic Republic, which has been accused of murdering tens of thousands of its own citizens in recent weeks.
The US president has described the death of Khamenei as the "single greatest chance for the Iranian people to take back their country".
And he has claimed that many people in the Revolutionary Guard, military and other security and police forces "no longer want to fight".
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Dubai hotels hit during Iranian missile fire
How have Iranians reacted to death of supreme leader?
Before the Iranian revolution Iran was ruled by a monarchy, with the king called the "shah".
Reza Pahlavi, the US-based son of the shah who was deposed in the 1979 revolution has said: "With (Khamenei's) death, the Islamic Republic has in effect reached its end and will very soon be consigned to the dustbin of history."
Any attempts to appoint a successor to Khamenei are "doomed to fail from the outset", Pahlavi added, claiming they will have neither longevity nor legitimacy.
He has urged Iran's military, law enforcement and security forces to take their "final opportunity to join the nation".
Maritime activity has been almost brought to a standstill as the US and Iran have traded strikes.
Hundreds of tankers are usually travelling through the Strait of Hormuz between Persian Gulf and the Gulf of Oman at all times, with Iran to the north and Oman and the United Arab Emirates to the south. It's the only marine outlet for this region's main oil producers including Iran.
In 2024, around a fifth of all global oil was flowing through the narrow waterway - the equivalent of 20 million barrels a day.
A snapshot from a month ago on February 1 shows how busy the waterway is with vessels passing into and out of the waterway.
On February 28, the day after the US and Israel carried out their first strikes on Iran, far fewer vessels were in the area and very little movement. By March 1, very few ships were in the straight, and vessels appeared to cluster around large ports either side of the strait.
Sky's Data and Forensic team tracked several individual tankers. One - the KHK Empress - was already in the strait before turning back on Saturday at around 10:00 AM UTC. By Saturday evening, 4 others had turned away from the strait to head back out into the Gulf. And by Sunday they were all on the move out of the region.
Analytics agency Kpler estimates that these five ships have the capacity to carry around 10 million barrels of oil.
Fear of being targeted on the route are not unfounded. On March 1, a Palau-flagged oil tanker 'The Skylight' was attacked. Four people were injured and the whole crew of 20 people was evacuated.
The US navy is warning against navigation through the strait and some traders are suspending transit.
And interference to the ship tracking and communication system, AIS, is making the area even more dangerous. The images below show AIS signals, which ships use to broadcast their locations, on February 27 compared to 28 February.
The later image shows distorted signals, with ships broadcasting locations that appear to be far from their true positions, or even on land.
Volatility in the Gulf will have an impact across the world. Disruption here will in turn disrupt global markets and international trade.
Clouds of smoke and the crack of high explosives rupture the air as the Americans and the Israelis bring their operation to the heart of the capital city.
And if the elimination of the senior Iranian leaders was their chief objective, it seems they have achieved their goal.
The death of the Supreme Leader, Ayatollah Ali Khamenei, was acknowledged on state television at 4am on Sunday. The presenter recited a prayer for the dead - but he was barely able to finish it as he choked back the tears.
In stark contrast, the demise of the supreme leader has been met with a burst of exuberance and sheer joy in locations throughout the country.
"Congratulations on our freedom", cried one in the back seat of a car.
"Am I dreaming? Hello to the new world!" shouted another in southern Iran, as he watched people tear down a monument to Ayatollah Khomeini, the founder of the Islamic Republic.
In Tehran, many cheered from the windows and lit fireworks from their balconies. Khamenei ruled Iran with an iron fist - an autocratic leader prepared to repress and kill his own people to protect the regime.
But in a deeply polarised society, he was also a revered religious figure - a man invested with the authority of the divine.
Anger and shock among some Iranians
In Tehran's Revolution Square, his supporters spoke of their anger and deep shock.
"We were saying to ourselves all night that his death must be a lie. Unfortunately, it was the truth," said one woman, as her body shook heavily with emotion.
"We lost our dearest person, we lost our elder, we lost our master," said another tear-stained man.
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President Trump says he has given Iranians the opportunity to take back their country but it is clear that a significant number back the existing regime.
A regime this coalition of two is now trying to destroy.
We saw the remains of the police headquarters in Tehran and the bombed-out shell of the Revolutionary Prosecutor's Office, where many political dissidents have been sentenced to death.
One massive blast claimed the detention facilities used the feared paramilitary police or 'Basij'.
The regime certainly looks vulnerable as the Americans and the Israelis operate with what appears to be total air superiority.
Yet the clerics and their supporters remain and they control the streets.
If you wanted proof that war, even this war, is not just about aerial defences and surgical strikes, this was it. A ghastly vista of sudden death.
When we arrived on the scene, we were told, repeatedly, that this was just a place where people lived, prayed and got taught. No military base, no hardware, not even a government office.
"Why would this be a target," said one person. "There is no excuse."
What we saw when we arrived was a chaotic aftermath. What we heard was a horror story.
Dozens of residents had gone to the bomb shelter after receiving an alert on their phone and then hearing an air raid siren. It is the sort of behaviour that is, at once, disconcerting and also normal.
Thanks to previous conflicts, including the 12-day war just eight months ago, Israelis are accustomed to getting such warnings.
The shelter was supposed to be their sanctuary. Instead, it became a tomb in a matter of moments.
The missile somehow evaded Israel's formidable air defences.
"Nothing can be one hundred percent effective," said one Israeli military official to me. "We cannot stop every single missile. We can try, but we know that eventually one will get through."
And so it did, devastatingly. We watched as huge diggers were brought in to try to clear the rubble, and as search and rescue teams worked out how to look for survivors. There were soldiers, emergency workers, local residents, police and politicians.
We spoke to one of them, Amichai Eliyahu, Israel's outspoken culture minister. He was surveying the destruction, his head shaking. This, he said, was an embodiment of why Israel needed to fight Iran.
"What did these people here ever do to them? What did these babies do to harm them?" he said to me.
"They have never done anything bad to Iran, we don't even share a border with Iran. This was done for no reason at all, except pure hatred for the sake of hatred. So I'm asking all those who defend them in the world, who are you defending? Monsters, Monsters want to kill us."
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Which Iranian officials are dead?
Attacks close Middle East airports
Lieutenant Colonel Yochay Manoff was more sanguine, when we spoke on a ridge overlooking the scene. He is a company commander in Israel's National Rescue Unit, accustomed to difficult situations and traumatic problems.
But, for him, this one was difficult to accept.
"Just for reference, this is one missile that hit and affected so many buildings and so many lives," he told me. "Think about the amount of missiles that were on the way from Iran to Israel over the last two days. The damage could be immense."
Could be, but hasn't been. Israel puts so much store by its aerial defence systems that sometimes its citizens can appear complacent, so confident are they in the military technology.
But this was proof that nothing works perfectly, all of the time.
Every now and then a missile will get through the array of defence systems that guard Israel's airspace, and sometimes they strike with horrific impact. This corner of Beit Shemesh offered grim evidence of that.