All six workers missing after the Francis Scott Key Bridge in Baltimore collapsed Tuesday are presumed dead, and the search for them has been suspended until Wednesday morning.

Roland L. Butler Jr., superintendent for Maryland State Police, said in the evening that the search and rescue mission was transitioning to one of search and recovery. He said divers would return to the site at 6 a.m. the following day, when challenging overnight conditions are expected to improve.

A cargo ship lost power and rammed into the bridge early Tuesday, destroying the span in a matter of seconds and plunging it into the river in a terrifying collapse.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

The Francis Scott Key Bridge in Baltimore collapsed early Tuesday after a support column was hit by a large container ship that had lost power, sending vehicles and people into the Patapsco River, authorities said.

Radio traffic obtained from the Broadcastify.com archive indicates officers were just about to alert a construction crew when a major bridge in Baltimore collapsed after being hit by a container ship that had lost power.

The Maryland Transportation Authority first responder radio traffic includes a dispatcher putting out a call saying a ship had lost its steering ability and asking officers to stop all traffic. It took officers less than two minutes to stop traffic on the bridge.

One officer who had stopped traffic radioed that he was going to drive onto the bridge to notify the construction crew once a second officer arrived. But seconds later, a frantic officer radioed that the bridge had collapsed.

The six people still unaccounted for were part of the construction crew, which was filling potholes on the bridge.

A senior executive of the company that employed the construction workers said six of the company’s workers are presumed to be dead and one worker was hospitalized.

Jeffrey Pritzker, executive vice president of Brawner Builders, said the crew was working in the middle of the bridge’s span when the crash happened and crumbled the bridge.

The bodies of the workers have not yet been recovered, but they are presumed to have died given the water’s depth and the amount of time that has passed since the crash, he said.

Sonar has indicated that there are vehicles in the water, where the temperature 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.

Earlier, Kevin Cartwright, director of communications for the Baltimore Fire Department, told The Associated Press that several vehicles were on the bridge at the time, including one the size of a tractor-trailer truck.

He called the collapse a “developing mass casualty event,” though he didn’t know at the time how many people were affected.

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 two pilots were in control. It said all crew members, including the pilots, were accounted for and there are no reports of any injuries.

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.

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.