Local police, who responded to a call shortly after 6am, say they were shot in a "domestic disturbance" at different homes.
Shreveport police spokesperson Chris Bordelon said 10 people were shot in total and some of the eight children who died were related to the gunman.
He said the suspect stole a car while fleeing the scene of the shootings and was shot and killed by police during a chase.
Mr Bordelon said the crime scene extended across three locations, adding: "This is an extensive scene unlike anything most of us have ever seen."
At a news conference outside a home where one of the shootings occurred, officials requested patience and prayers from the community.
Shreveport Police Chief Wayne Smith said: "I just don't know what to say, my heart is just taken aback...I cannot begin to imagine how such an event could occur."
The city's mayor Tom Arceneaux said: "This is a tragic situation - maybe the worst tragic situation we've ever had," adding: "It's a terrible morning."
In a statement, state police said their detectives have been asked to to investigate and that no officers were harmed in the shooting of the suspect.
Louisiana Governor Jeff Landry said in a statement he and his wife were heartbroken.
"We're deeply grateful to the law enforcement officers and first responders working tirelessly on the scene," he added.
A Northern Ireland Fire and Rescue Service spokesperson said they received a call about the incident shortly after 8pm on Sunday.
"Currently, 42 firefighters from stations in Ballycastle, Ballymoney and Portrush are attending," the spokesperson said.
Local residents have been advised to keep windows and doors closed and to avoid the area.
Sinn Fein councillor Cara McShane said the fire is at the Antrim Arms, a former hotel, which she described as a "cornerstone of heritage in the town".
"I am deeply concerned by the devastating fire at the Antrim Arms in Ballycastle," she said.
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"My immediate thoughts are with local residents and businesses who will be affected by this incident."
Various crews are involved in tackling the blaze, including teams from Northland, Springfield and Kilrea.
Metropolitan Police deputy commissioner Matt Jukes said Britain's Jewish community is facing "a concerted campaign" after the latest incidents, including an attempted 'firebomb' attack at a synagogue in northwest London on Saturday night.
He said bins were targeted outside a communal block on the same evening following an attack on a building previously used by a Jewish charity in Hendon, northwest London, on Friday by a man who lit a plastic bag at the entrance before fleeing.
Follow latest: Updates on investigation
Met deputy assistant commissioner Vicki Evans said most of the recent incidents have been claimed online by the Ashab al-Yamin group, which has been publicly linked to Iran.
The group have also claimed similar attacks on Jewish communities across Europe in recent months.
Ms Evans said: "I've spoken previously about the Iranian regime's use of criminal proxies, and we're considering whether this tactic is being used here in London - recruiting violence as a service.
"Individuals carrying out these crimes often have no allegiance to the cause and are taking quick cash for their crimes."
"To anyone even considering getting involved - my message to you would be this - the stakes are high - and it is absolutely not worth the risk for a small reward."
She warned anyone caught for their involvement in the crimes will be prosecuted, including for offences under the National Security Act.
Mr Jukes said "thugs for hire who commit criminal acts and intimidation on behalf of others" would face long prison sentences in a press conference outside the Kenton United Synagogue, in Harrow.
Officers on patrols in the wake of the previous incidents spotted damage to a window at around midnight and saw smoke inside a room as well as evidence that a "bottle with some sort of accelerant had been thrown".
The force said the incident is being treated as arson.
The synagogue is close to a school and a children's playground. By Sunday morning, the area was under a large police cordon, with forensics officers, fire investigation dogs and plainclothes officers at the scene.
A Campaign Against Antisemitism spokesperson said: "Last night, another Jewish synagogue in London was firebombed, this time in Kenton. Thankfully, the damage was limited."
A spokesperson for the Community Security Trust (CST) said the attack caused "minor smoke damage to an internal room, but there were no injuries and no significant structural damage".
The UK's Chief Rabbi Sir Ephraim Mirvis has called the attack "cowardly" and said "a sustained campaign of violence and intimidation against the Jewish community of the UK is gathering momentum".
It comes a day after an arson attack on a building that used to house a Jewish charity elsewhere in northwest London, which is also being investigated as an antisemitic hate crime.
London Mayor Sadiq Khan said the Metropolitan Police have "stepped up resources" in the area.
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"There is no place for antisemitism in our city, and the perpetrators of these despicable attacks will face the full force of the law," he wrote in a post on X. "London will always stand united against those seeking to divide us."
Sir Keir Starmer said he was "appalled by recent attempted antisemitic arson attacks in North London" in a social media post.
"This is abhorrent and it will not be tolerated," the prime minister said. "Attacks on our Jewish community are attacks on Britain."
A building that used to belong to a Jewish charity in Hendon, northwest London, was attacked on Friday by a man who lit a plastic bag at the entrance before fleeing.
While Jewish Futures no longer uses the site, the signage still bears its name.
Police are also treating that attack as an antisemitic hate crime and no arrests have been made.
On Friday, suspicious items - including two jars containing powder - were found near the Israeli embassy in west London.
Police said the embassy was not attacked but officers are still investigating whether the items are connected to a video posted by an Iran-linked Islamist group, which claimed to have targeted the building with drones carrying dangerous substances.
The incidents followed a spate of other attacks in recent weeks. Last month, four ambulances run by a Jewish charity were burned down in Golders Green, north London, leading to four arrests.
Two people were also arrested this week after bottles of petrol were thrown at a synagogue in Finchley, northwest London.
The Metropolitan Police said officers were called to reports that a vehicle had been involved in a collision on Argyll Street, Westminster, at around 4.30am.
A man in his 50s sustained life-changing injuries and was taken to hospital, along with two women in their 30s, one of whom is in a critical condition. The second woman was treated for minor injuries.
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The driver of the car was arrested at the scene on suspicion of attempted murder, GBH, dangerous driving and drink driving. She remains in custody.
The incident, which took place in a busy part of central London, is not being treated as terrorism-related.
Detective chief inspector Alison Foxwell called for potential witnesses to come forward.
She said: "As our inquiries continue, our thoughts are with those injured and their loved ones.
"While this incident took place in the early hours of the morning, venues in the area were still open, and we believe a number of people will have seen what happened.
"I would urge anyone who witnessed the collision, or any activity prior to it that they feel may be of relevance, to come forward.
"The information you have - however minor you believe it may be - could be of crucial importance to investigators."
The US president has also revealed he's sending representatives back to Pakistan for further peace talks. The US delegation will arrive there on Monday evening, according to Mr Trump.
This would not leave long for discussions before the temporary truce ends on Wednesday, but a ceasefire being extended has happened before.
Here's everything we know about the talks:When is the deadline?
The ceasefire is due to run out on 22 April.
No date has been set for the next round of negotiations between Iran and the US, Iran's deputy foreign minister said on Saturday, noting that a framework of understanding must be agreed first.
The highest-level US-Iran talks since the 1979 Islamic Revolution, which took place in Islamabad last weekend, ended without agreement.
Who is involved?
In Mr Trump's Truth Social post on Sunday afternoon, in which he mentioned US representatives going to Pakistan, he didn't say which officials he would be sending to a second round of in-person talks with Iran in Islamabad.
Mr Trump's main negotiator will be JD Vance, the vice president, who was joined by special envoy Steve Witkoff and his son-in-law and former special adviser Jared Kushner last time.
The pair also negotiated a Gaza ceasefire deal and are involved in Russia-Ukraine talks.
Iranian officials said earlier on Sunday that they were still open to negotiation, but said ships wouldn't pass the strait while the US blockade remained in effect.
What do we know about the state of negotiations?
One of Iran's key negotiators has said there is "still some distance" in peace talks as the end of the two-week ceasefire approaches.
The first round of direct talks in Pakistan last week did not amount to much.
Pakistan's army chief was in Tehran this week, with Pakistani sources telling Reuters he made a breakthrough on "sticky issues" and both sides agree in principle. Pakistan has played a key role as a mediator in discussions between the two sides.
What do the different sides want?
Mr Trump described a 10-point proposal from Iran as a "workable basis on which to negotiate".
Mr Trump then posted on his social media site that the ceasefire was subject to Iran agreeing to the "COMPLETE, IMMEDIATE, and SAFE OPENING of the Strait of Hormuz".
Israel and the US both want Iran's missile capabilities to be significantly curbed. Tehran has said its formidable missile arsenal will not be the subject of negotiations.
A key objective since the start of the war from Mr Trump is that Iran can never be allowed to develop a nuclear weapon.
However, Tehran says its 10-point peace plan includes Washington's "acceptance of enrichment" of uranium for Tehran's nuclear programme.
An Iranian official said last week there are still "highly disputed issues" over Iran's nuclear ambitions.
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Iran also said that stopping hostilities in Lebanon will be part of larger peace negotiations.
Israeli Prime Minister Benjamin Netanyahu's office had said in a statement that a two-week suspension of strikes did not include the war with Hezbollah in Lebanon.
Iran wants the US to unblock Iranian assets and end sanctions that have crippled its economy for years.
The country also wants the withdrawal of US combat forces from the region.
Mr Trump has vowed to retain military assets in the Middle East until a peace deal is reached and warned of a major escalation in fighting if it failed to comply.
What is happening between Israel and Lebanon?
Israel and Lebanon agreed to implement a "cessation of hostilities" on 16 April for 10 days, according to a text of the deal released by the State Department.
The deal says Lebanon's government, with international support, would take "meaningful steps" to prevent Hezbollah and other groups from launching attacks on Israeli targets.
It also says that Israel and Lebanon recognise the country's security forces "as having exclusive responsibility for Lebanon's sovereignty and national defence", referencing a bid by the government since 2025 to disarm Hezbollah.
The deal does not require Israel to withdraw from southern Lebanon, where Israeli forces have been destroying villages and infrastructure after ordering residents south of the Litani River to leave.
What has happened in talks in recent days?
Mr Trump said on Friday there could be talks this weekend and that the two sides were "very close to making a deal".
He cited "very good conversations" with Tehran despite warning against "blackmail" over the important shipping channel.
Last week, the US and Iran ended an historic round of face-to-face discussions without coming to an agreement.
Tehran reversed course on Saturday to reassert control over the strait, with its closure throwing fresh doubt on the outcome of the war, which the US and Israel launched on 28 February.
Iran said it was responding to a continued US blockade of Iranian ports, adding it violated the ceasefire, while Iran's supreme leader Mojtaba Khamenei said Iran's navy was ready to inflict "new bitter defeats" on its enemies.
On Friday, Tehran announced the temporary reopening of the Strait of Hormuz following the 10-day ceasefire.
But Mr Ghalibaf warned that the shipping lane will stay closed if the US continues to block ships from entering and exiting Iran's ports.
What happened in the last round of talks?
US vice president JD Vance said negotiations finished without a deal after the Iranians refused to accept US terms to refrain from developing a nuclear weapon.
The discussions in Islamabad began last Saturday, a few days after a fragile ceasefire was announced, and as the war entered its seventh week.
"We were constantly in communication with the team because we were negotiating in good faith," Mr Vance said, with special envoys Steve Witkoff and Jared Kushner to his side.
"And we leave here, and we leave here with a very simple proposal, a method of understanding that is our final and best offer. We'll see if the Iranians accept it."
Mr Trump had said he would suspend attacks against Iran for two weeks.
Mr Vance's comments did not indicate what will happen after that time period expires or if the ceasefire will stay in place.
What about the Strait of Hormuz?
Iran has doubled down on its pledge to restrict ships passing through the strait as long as the US blockade of Iranian ports remains active.
On Friday, Iran had announced the temporary reopening of the strait, but it was closed again on Saturday evening.
Around a fifth of the world's traded oil typically flows through the strait every day.
Mr Ghalibaf said in a televised interview that Tehran would continue to threaten commercial vessels transiting the critical waterway.