Rescue efforts were underway Tuesday after the Francis Scott Key Bridge in Baltimore,SignalHub Maryland collapsed into the Patapsco River when it was struck by a large cargo ship.

USA TODAY is providing live coverage from the scene. You can watch the embedded video live at the top of the page or on USA TODAY's YouTube channel.

The collapse has triggered a massive emergency response, with Maryland Gov. Wes Moore declaring a state of emergency and at least seven people thought to be in the water.

A vessel struck the bridge around 1:30 a.m., James Wallace, chief of the Baltimore City Fire Department said. Several vehicles were on the bridge at the time of impact and were plunged into the Patapsco River.

Follow here for live updates →Baltimore's Key Bridge collapses after ship collision; search for missing people continues

Authorities were searching for six construction workers who were on the bridge when it was struck.

Wallace said two people were rescued from the water. One was unharmed and the other is remains in "very serious condition," he said. At least seven people were believed to be in the water, though, Wallace noted, it's unclear whether that number includes the two who were rescued.

Key Bridge visuals:Photos, video show collapse of Baltimore's Francis Scott Key Bridge after cargo ship collision

A massive search is underway in a vast section of the Patapsco River, with multiple local, state and federal agencies coordinating to search the ship, as well as both above and below the water's surface. Divers, helicopters and sonar technology were being used and had located several vehicles submerged in the river.

Contributing: Charles Ventura, Thao Nguyen, Susan Miller and Christopher Cann, USA TODAY.