The bridge reportedly collapsed after a ship hit a column of it.

A spokesperson for the Baltimore City Fire Department told The Baltimore Sun a major rescue operation was underway with all lanes closed and with all traffic being rerouted from the 1.6-mile steel bridge that is part of Interstate 695.

“The entire bridge collapsed into the Patapsco River,” Kevin Cartwright, the director of communications for the Baltimore Fire Department, told the newspaper.

“We have reason to believe that there were vehicles and possibly a tractor-trailer” that went into the water, Cartwright said.

Several video footage of the ship hitting the bridge have now gone viral on the social media.

All traffic is being detoured, Maryland Transportation Authority was quoted as saying by CNN, and It’s unclear if anyone was injured.

Baltimore Mayor Brandon Scott says he is aware of the development around the bridge collapse.

"I'm aware of and en route to the incident at the Key Bridge. I have been in contact with @BaltimoreFireChief Wallace,@GovWesMoore@JohnnyOJr, and @AACoExec
. Emergency personnel are on scene, and efforts are underway," he posted on X.

The four-lane bridge extends over the Patapsco River.

The bridge is 3km (1.6 mile) long.

It is part of the 695 highway that circles Baltimore city.