Witness says 'holy hell' after seeing Baltimore bridge has collapsed into the water

A witness to the Francis Scott Key bridge collapse in Baltimore could do little other than say 'holy hell' as he watched the scale of destruction unfold.

The bridge in Baltimore collapsed in a matter of seconds after being struck by a container ship at around 1:30am local time this morning (26 March), with local authorities saying 'seven people and several vehicles' had gone into the water.

The bridge had been struck by container ship Dali, which had left port in Baltimore minutes earlier, and within seconds the large structure spanning the Patapsco River had collapsed.

Rescue services have since declared the bridge collapse to be a 'mass casualty event', though they are not yet clear on the scale of casualties as they are searching for people who might have gone into the water.

A video shared by witness Bobby Gattus showed the extent of the damage as he panned his camera across the river and there was virtually nothing left.

"Wanted to know what the bang was," he said at the beginning of his video as he panned his camera across the darkened surface of the river.

"Ship hit the Key bridge... sinking, the bridge is gone," he said as he zoomed in on the few remaining traces of the Francis Scott Key bridge before saying 'holy hell'.

Previous footage of the incident showed the container ship Dali striking a support pillar in the early hours of Tuesday morning in Baltimore, resulting in the bridge collapsing within seconds.

Rescue efforts are underway and the BBC reports that a team of divers are on the scene and carrying out rescue operations, with the water temperature being around -1C and thus a danger to anyone who survived the bridge collapse in and of itself.

The Baltimore City Fire Department has said that as many as 20 people might have gone into the water.

First opened in 1977, the Francis Scott Key bridge is named after the author of the US national anthem.

Some people who journeyed across the bridge before the collapse had said they found the experience 'scary', with a 56 metre drop from the bridge down to the surface of the water.

While the status of people who might have gone into the water with the bridge's collapse is currently unknown, shipping company Synergy Marine Group have said that nobody on board the container ship was injured.

They confirmed that all crew members on board the Dali were present and accounted for without injury.