The Francis Scott Key Bridge in Baltimore collapsed on Tuesday night after the Singapore-flagged cargo ship struck it, sending vehicles plunging into the water.
Rescuers pulled out two survivors, one in very serious condition, and were searching for more in the Patapsco River.
Eight people were on the bridge at the time of the collision and six remain unaccounted for after the collapse, which closed one of the busiest ports in the United States.
The US Coast Guard deployed crews for an active search and rescue mission.
“This is a dire emergency,” Kevin Cartwright from the Baltimore Fire Department said.
“Our focus right now is trying to rescue and recover these people.”
He called the collapse a “developing mass casualty event”.
Maryland Governor Wes Moore said the bridge was up to code and there were no known structural issues.
He said the ship’s crew alerted authorities to a power issue onboard before the collision.
Traffic was suspended at the Port of Baltimore until further notice, Maryland transportation authorities said.
It is the busiest US port for car shipments, handling more than 750,000 vehicles in 2022, according to port data.
It could create bottlenecks and increase delays and costs on the northeastern seaboard, experts say.
– with AAP
