The 1.6-mile (2.57 km) long Francis Scott Key Bridge in Baltimore, Maryland, collapsed in the early hours of Tuesday after a container ship hit it, and as many as seven people may be in the water, officials said.

A live video posted on YouTube showed a ship hitting the bridge, after which several of its spans collapsed into the Patapsco River. Unverified videos posted on social media X also showed the impact and collapse. Reuters could not immediately verify the videos.

The Baltimore City Fire Department described the collapse as a mass-casualty incident, and said workers were searching for seven people in the river.

"We received several 911 calls at around 1:30 am, that a vessel struck the Key Bridge in Baltimore, causing the collapse. This is currently a mass casualty incident and we are searching for seven people who are in the river," Kevin Cartwright, director of communications for the Baltimore Fire Department told Reuters.

Baltimore police said they had been notified of the incident at 1:35 a.m. ET (535 GMT) on Tuesday.

The Associated Press reported that multiple vehicles had fallen into the water.

Ship tracking data from LSEG shows a Singapore-flagged container ship, the Dali, at the location along the Key Bridge where the accident occurred. The registered owner of the ship is Grace Ocean Pte Ltd and the manager is Synergy Marine Group, LSEG data show.

Synergy Marine Corp said that a Singapore-flagged container ship “Dali” collided with one of the pillars of the bridge and that all its crew members, including the two pilots have been accounted for and there were no reports of any injuries.

Reuters could not immediately reach Grace Ocean for comment.

"All lanes closed both directions for incident on I-695 Key Bridge. Traffic is being detoured," Maryland Transportation Authority said in a post on X.

It was not immediately clear if the Baltimore port operations were impacted due to the bridge collapse.

The port's private and public terminals handled 847,158 autos and light trucks in 2023, the most of any U.S. port. The port also handles farm and construction machinery, sugar, gypsum and coal, according to a Maryland government website.

The Baltimore port did not immediately respond to Reuters' request for comment.

"I'm aware of and en route to the incident at the Key Bridge... Emergency personnel are on scene, and efforts are underway," Baltimore Mayor Brandon Scott on X.

The bridge, named after Francis Scott Key, opened in 1977 and cost an estimated $60.3 million.