Efforts are underway to rescue people and vehicles that plunged into the Patapsco River in Baltimore after a ship hit a bridge causing a major thoroughfare to collapse early on Tuesday morning.

About 1.30am local time (5.30 GMT) the 9,962-teu container ship Dali (built 2015), operated by AP Moller-Maersk, crashed into the Francis Scott Key Bridge, causing the main span to fall into the river.

The collapse has been called a “mass casualty event” by the Baltimore City Fire Department and the US Coast Guard has scrambled rescue vessels from two stations to the scene. Maryland Governor Wes Moore has declared a state of emergency.

The Port of Baltimore is one of the largest ports in the US by total tonnage and is in the top 10 for handling dry bulk cargoes, according to federal government statistics.

The Maryland Port Administration, which runs the port, said it is also one of the top ro-ro ports in the country.

Follow TradeWinds coverage of the disaster here