A major search and rescue operation is under way to find six construction workers believed to be on a Baltimore bridge when it collapsed after being hit by a fully-laden container ship overnight.
The four-lane Francis Scott Key Bridge crumpled into the frigid waters of the harbour and Patapsco River about 1.30am local time.
The BBC has reported that local construction crews were fixing pot holes on the bridge at the time it collapsed.
At least six people were unaccounted for. Two were rescued from the water, one in a serious condition.
Divers were among the search crews and Baltimore fire officials said vehicles had been detected in the water by sonar, the BBC said.