The cargo ship had issued a mayday call to alert authorities it had lost power before it collided with the Baltimore bridge on Tuesday morning.

Following the call, Maryland Transportation Authority Police Dispatch and Response officials acted swiftly, shutting down the north and south sides of the bridge.

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In the audio, one official instructs: "Hold all traffic on the Key Bridge... There's a ship approaching that just lost their steering so until we get that under control, we've got to stop all traffic.

"Make sure no one's on the bridge right now. There's a crew up there… You might want to notify the foreman to see if we can get them off the bridge temporarily."

Another responds saying he would "grab the workers" but it was too late.

A second later, a voice is heard saying: "The whole bridge just fell down. Start, start whoever… everybody. The whole bridge just collapsed."

In other developments, investigators at the National Safety Transportation Board have confirmed that the cargo ship's data recorder has now been recovered - and they are examining whether contaminated fuel played a role in the crash.

The Dali ship ploughed into one of the bridge's supports and, in an instant, the 1.6-mile-long structure had fallen into the Patapsco River, along with vehicles and workers who were on it at the time.

Six workers missing after the collapse are presumed dead, the executive vice president of Brawner Builders has confirmed.

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Officials say the rescue mission for the group has now become a recovery operation.

It comes as Miguel Luna, from El Salvador, was named as one of the six people on the Francis Scott Key Bridge when it collapsed.

All 22 crew members on board the ship, including the two pilots, have been accounted for and there were no reports of injuries.

Maryland Governor Wes Moore said he spoke to the families of the victims, assuring them since the mission had transitioned from search and rescue to recovery he would "put every possible resource to bring [them] a sense of closure".

He praised the "true heroism" of the first responders who "saved countless lives that night".

Mr Moore also said he was "overwhelmed" by the amount of support from both the Democratic and Republican parties as he stressed the importance of getting the bridge rebuilt.

Meanwhile, US President Joe Biden has promised that he will visit Baltimore "as soon as possible", adding that the federal government will cover the "full cost" of rebuilding the bridge - which experts say could be over $600m (£474m).

He told reporters: "Everything so far indicates that this was a terrible accident. At this time we have no other indication, no other reason to believe there's any intentional act here.

"Personnel on board the ship were able to alert the Maryland Department of Transportation that they had lost control of their vessel."

Mr Biden added that this meant local authorities were able to close the bridge before it was struck, which "undoubtedly saved lives".

He continued: "Our prayers are with everyone involved in this terrible accident and all the families [affected], especially those waiting for news of their loved one right now. I know every minute in that circumstance feels like a lifetime."

The Key Bridge carries the Interstate 695 highway over the Patapsco River southeast of the Baltimore metropolitan area.

Its main section spans 1,200 feet and was one of the longest continuous truss bridges in the world upon its completion, according to the National Steel Bridge Alliance.

The Dali was previously involved in a minor incident when it hit a quay at the Port of Antwerp in Belgium in 2016, where it was damaged, according to Vessel Finder and maritime accident site Shipwrecklog.