In an instant, a large section of the Francis Scott Key Bridge was gone – as dozens of its steel beams collapsed into the water after being hit by a cargo ship.
Emergency services are still at the scene and details about casualties are still emerging.
Sky News has spoken to a number of maritime and engineering experts to try and understand what might have happened – and what issues may have been at play.
Image: The Singapore-flagged container ship ‘Dali’ after it collided with the bridge. Pic: Reuters
Was human error to blame?
Professor Helen Sampson, an expert at the Seafarers International Research Centre at Cardiff University, says the crash may have been caused by someone’s mistake.
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She told Sky News: “Was there some sort of miscommunication or misunderstanding between the pilot and the crew? Or was there a pilot error?”
The time of day when the disaster occurred – around 1.30am local time – gives rise to concerns about tiredness, she added.
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“The time makes me also wonder whether there was an element of fatigue at play…
“It’s almost always the case that we focus on human error at the individual level, it’s almost always the case that there’s a broader context which has resulted in that human error, like fatigue and the demands made on pilots or on crews.”
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0:46
‘They thought it was an earthquake’
What about a mechanical problem?
However, another maritime safety expert says the “most likely” cause of the crash was a failure in the ship’s machinery.
David McFarlane, director of Maritime Risk and Safety Consultants Ltd, told Sky News: “The first thing that springs to my mind is: was there a sudden fault with the ship’s engines or the steering gear?”
Mr McFarlane said a human error was less likely because of the number of people who would have been on duty.
“There should be no room for one-person errors because one of the other people should jump in and say ‘hang on’,” he said.
“The most likely cause of this is a failure in machinery or steering gear, but we just won’t know until the authorities have been on board. And even then, they’re unlikely to say what’s been going on for some considerable time.”
Prof Sampson said a mechanical failure with the steering gear or something similar would be the “most dramatic” explanation for what happened.
Officials have confirmed the ship that crashed into the bridge had issued a mayday call and had lost power.
Image: The remains of the bridge on top of the ship. Pic: Jim Lo Scalzo/EPA-EFE/Shutterstock
Was there a design flaw in the bridge?
Opened in 1977, the Francis Scott Key Bridge is named after the poet who wrote the words to the Star Spangled Banner, the American national anthem.
Constructed from steel, it was 1.6 miles long and not dissimilar to some bridges in the UK, one expert told Sky News.
Julian Carter, a structural and civil engineering expert, said these structures are simple in concept – but “very weak” at certain points.
“It’s what we call a continuous structure every little piece is connected to another – and unfortunately it’s a catastrophic collapse.”
Professor Barbara Rossi, an expert in engineering science at the University of Oxford, said the impacting force of the cargo ship must have been “immense” to lead to the collapse of the concrete structures underpinning the bridge.
“We should not speculate around if such huge impact forces should have been taken into account at the design stage,” she added.
There has also been discussion about whether “dolphins” (steel structures embedded in the seabed to stop or divert a ship) or artificial islands may have been inadequate.
Bridge designer Robert Benaim said: “I do not know what the arrangements were for this bridge but major bridges over shipping lanes must have substantial protection for piers or columns.”
He added: “If piers are not protected adequately then they are vulnerable to ship collision. Clearly the protection of the piers in this instance was inadequate. A pier or column of a bridge could never resist the impact of a large ship. They must be protected from collision.”
Palestinian President Mahmoud Abbas and 80 other officials have been blocked from attending September’s annual meeting of the United Nations General Assembly in New York.
US secretary of state Marco Rubio has revoked the US visas of delegates from the Palestinian Authority (PA) and Palestine Liberation Organisation (PLO), and denied others from applying for one.
It is the latest step by Donald Trump’s administration to target Palestinians with visa restrictions, and follows the suspension of a programme to allow injured children from Gaza to receive treatment in the US.
Image: Mahmoud Abbas addressed the general assembly in 2024, but is barred from next month’s meeting. Pic: Reuters
“It is in our national security interests to hold the PLO and PA accountable for not complying with their commitments, and for undermining the prospects for peace,” a statement from the US State Department said.
It added that, to be considered partners for peace, both groups “must consistently repudiate terrorism, and end incitement to terrorism in education, as required by US law and as promised by the PLO”.
Israel declared Gaza’s largest city a dangerous combat zone on Friday.
The army launched a planned offensive that has drawn international condemnation.
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Thick smoke rises from Gaza City after Israeli strikes
Foreign ministers from Iceland, Ireland, Luxembourg, Norway, Slovenia and Spain released a joint statement saying the military operations in Gaza City will cause “intolerable deaths of innocent Palestinian civilians”.
Hundreds of thousands of Palestinians are sheltering in Gaza City while enduring famine.
Image: An Israeli armoured vehicle in northern Gaza on Friday. Pic: AP
Image: Palestinians ride a truck carrying humanitarian aid in Gaza City. Pic: AP
The Palestinian ambassador to the United Nations (UN), Riyad Mansour, said Mr Abbas had planned to lead the delegation to the UN meetings and was expected to address the general assembly at the general debate, which begins on 23 September.
He was also expected to attend a high-level meeting co-chaired by France and Saudi Arabia on 22 September about a two-state solution, a broad idea involving Israel coexisting with an independent Palestinian state.
The State of Palestine is an observer member of the UN, meaning it can speak at meetings but not vote on resolutions.
Image: The State of Palestine cannot vote on UN resolutions. Pic: AP
US decision ‘contravenes international law’
The Palestinian Authority “expressed its deep regret and astonishment” at the visa decision, calling it “a violation of US commitments” as the host of the UN, and claiming it “contravenes international law”.
UN spokesman Stephane Dujarric said the world body would be seeking clarification in the “hope that this will be resolved”.
Image: Hundreds of diplomats left when Israeli leader Benjamin Netanyahu began speaking at the general assembly in 2024. Pic: Reuters
The State Department said that the Palestinian Authority’s mission to the UN, comprising officials who are permanently based there, would not be included in the restrictions.
Under a 1947 UN agreement, the US is generally required to allow access for foreign diplomats to the UN in New York.
But Washington has said it can deny visas for security, extremism and foreign policy reasons.
The death toll in Gaza has now risen to 63,025, according to the Hamas-run health ministry, which does not differentiate between civilians and combatants.
It also reported five more malnutrition-related deaths in the last 24 hours, bringing the total number during the war to 322, with 121 of them children.
US President Donald Trump has revoked Secret Service protection for former vice president and 2024 Democratic rival Kamala Harris.
A senior adviser to Harris, Kirsten Allen, confirmed the decision. “The vice president is grateful to the United States Secret Service for their professionalism, dedication, and unwavering commitment to safety,” said the adviser.
Typically, vice presidents receive a six-month security detail from the Secret Service after they leave office, although it had been extended to 18 months for Harris, according to officials.
Initially, then-president Joe Biden extended her security arrangements to one year, or January 2026, according to reports.
However, a Secret Service official told Sky News’ US partner, NBC, that Biden subsequently signed an executive memorandum in January increasing the then vice-president’s protection period even further, to 18 months.
Former US presidents receive Secret Service protection for life.
Harris, who lost the 2024 presidential election to Mr Trump, is due to start a book tour for her memoir, “107 Days”, shortly.
She was the Democratic nominee for 107 days after Biden exited the race in the weeks following a challenging debate against Trump.
Mr Trump has also ended federal security protection for others, including former national security adviser John Bolton. Last week, FBI agents raided Bolton’s Maryland home.
In March, the president ended protection for Joe Biden’s children – Hunter and Ashley Biden.
Harris has not ruled out a possible presidential run in 2028. She announced in July that she would not run for governor of California in 2026.
Eighteen other people were injured, including children aged between six and 15 and three adults in their 80s.
Police said Robin Westman, a male born as Robert Westman, opened fire with a rifle through the windows of the school’s church as children sat in pews.
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17:49
New details released of US school shooting
‘Our hearts are broken’
Harper’s parents, Michael Moyski and Jackie Flavin, remembered her as “a bright, joyful, and deeply loved 10-year-old whose laughter, kindness, and spirit touched everyone who knew her”.
“Our hearts are broken not only as parents, but also for Harper’s sister, who adored her big sister and is grieving an unimaginable loss. As a family, we are shattered, and words cannot capture the depth of our pain,” their statement said.
They urged leaders and communities to “take meaningful steps to address gun violence and the mental health crisis in this country.”
“Change is possible, and it is necessary – so that Harper’s story does not become yet another in a long line of tragedies,” the statement added.
Image: The family of Fletcher Merkel said there was a ‘hole in our hearts’. Pic: Family handout/AP
‘Fletcher loved his family’
In a statement reported by Sky’s US partner network NBC News, Fletcher’s father Jesse Merkel blamed the “coward” killer for why the boy’s family can’t “hold him, talk to him, play with him, and watch him grow into the wonderful young man he was on the path to becoming”.
He said: “Fletcher loved his family, friends, fishing, cooking, and any sports that he was allowed to play.
“While the hole in our hearts and lives will never be filled, I hope that in time, our family can find healing.”
Mr Merkel also praised “the swift and heroic actions of children and adults alike from inside the church”.
“Without these people and their selfless actions, this could have been a tragedy of many magnitudes more. For these people, I am thankful,” he added.
Image: Families and loved ones reunite at the scene after the shooting. Pic: Reuters
Mayor calls for assault weapon ban
It comes after Minneapolis mayor Jacob Frey called for a statewide and federal ban on assault weapons, a day after the deadly school shooting.
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Minneapolis mayor urges assault weapons ban
“Thoughts and prayers are not going to cut it. It’s on all of us to see this through,” the mayor said at a news conference. “We need a statewide and a federal ban on assault weapons.
“We need a statewide and a federal ban on high-capacity magazines. There is no reason that someone should be able to reel off 30 shots before they even have to reload.
“We’re not talking about your father’s hunting rifle gear. We’re talking about guns that are built to pierce armour and kill people.”
“It is very clear that this shooter had the intention to terrorise those innocent children,” he added, before saying the killer “fantasised” about the plans of other mass shooting attackers and wanted to “obtain notoriety”.
Thomas Klemond, interim CEO of Minneapolis’s main trauma hospital Hennepin Healthcare, said at an earlier news conference that the hospital was treating nine patients injured in the shooting.
One child at the hospital was in a critical condition, he added.
Children’s Minnesota Hospital also said that three children remain in its care as of Thursday morning.