BALTIMORE - A container ship rammed into a major bridge in Baltimore early Tuesday, causing it to snap in a few places and plunge into the river below. Several vehicles fell into the chilly waters, and rescuers were initially searching for at least seven people.

Two people were pulled from the waters, one in serious condition, according to Baltimore Fire Chief James Wallace. He said authorities “may be looking for upwards of seven people” but he said that number could change. It was not clear if the two rescued were included in the seven.

The vessel appears to have crashed into one of the supports of the Francis Scott Key Bridge, according to a video posted on X, formerly known as Twitter. The ship caught fire, and thick, black smoke billowed out of it.

“This is a dire emergency,” Kevin Cartwright, director of communications for the Baltimore Fire Department, told The Associated Press. Though he said it was too early to know how many people were affected, he called the collapse a “developing mass casualty event.”

The temperature in the river was about 47 degrees Fahrenheit (8 degrees Celsius) in the early hours of Tuesday, according to a buoy that collects data for the National Oceanic and Atmospheric Administration.

Cartwright added that some cargo appeared to be dangling from the bridge, which spans the Patapsco River at the entrance to a busy harbor. The river leads to the Port of Baltimore, a major hub for shipping on the East Coast. Opened in 1977, the bridge is named for the writer of “The Star-Spangled Banner.”

Maryland Gov. Wes Moore declared a state of emergency and said he was working to get federal resources deployed. The FBI was also on the scene.

Synergy Marine Group - which owns and manages the ship called the “Dali” - confirmed the vessel hit a pillar of the bridge at about 1:30 a.m. while it was in control of two pilots. It said all crew members, including the pilots, were accounted for and there are no reports of any injuries.

Several vehicles were on the bridge at the time, including one the size of a tractor-trailer truck, according to Cartwright.

From a vantage point near the entrance to the bridge, jagged remnants of its steel frame were visible protruding from the water, with the on-ramp ending abruptly where the span once began.

A vessel called Dali was headed from Baltimore to Colombo, Sri Lanka, as its final destination, according to Marine Traffic and Vessel Finder. The ship was flying under a Singapore flag, WTOP radio station reported, citing Petty Officer Matthew West from the Coast Guard in Baltimore.

Mayor Brandon M. Scott and Baltimore County Executive Johnny Olszewski Jr. posted that emergency personnel were responding and rescue efforts were underway.

“All lanes closed both directions for incident on I-695 Key Bridge. Traffic is being detoured,” the Maryland Transportation Authority posted on X.

In 2001, a freight train carrying hazardous materials derailed in a tunnel in downtown Baltimore and caught fire, spewing black smoke into surrounding neighborhoods and forcing officials to temporarily close all major roads into the city.