Crews begin first salvage of collapsed Baltimore bridge

Salvage crews are working to lift the first piece of Baltimore's collapsed Francis Scott Key Bridge from the water to allow barges and tugboats to access the disaster site, the first step in a complex effort to reopen the city's blocked port.

The steel truss bridge collapsed early on Tuesday morning, killing six road workers, when a massive container ship lost power and crashed into a support pylon. Much of the span crashed into the Patapsco River, blocking the Port of Baltimore's shipping channel.

Maryland Governor Wes Moore told a news conference on Saturday that a section of the bridge's steel superstructure north of the crash site would be cut into a piece that could be lifted by crane onto a barge and brought to the nearby Tradepoint Atlantic site at Sparrows Point.

"This will eventually allow us to open up a temporary restricted channel that will help us to get more vessels in the water around the site of the collapse," Moore said.

He declined to provide a timeline for this portion of the clearance work.

Maryland Bridge Collapse
Sparks fly as workers begin to remove a section of Baltimore's collapsed Francis Scott Key Bridge. (AP PHOTO)

Workers will not yet attempt to remove a crumpled part of the bridge's superstructure that is resting on the bow of the Dali, the 984-foot Singapore-flagged container ship that brought down the bridge. Moore said it was unclear when the ship could be moved, but said that its hull, while damaged, is "intact".

"This is a remarkably complex operation," Moore said of the effort to clear bridge debris and open the Port of Baltimore to shipping traffic.

The bodies of two workers who were repairing the bridge deck at the time of the disaster have been recovered, but Moore said efforts to recover four others presumed dead remain suspended because conditions are too dangerous for divers to work amid too much debris.

Saturday's operation involves cutting a piece just north of that channel and lifting it with a 160-ton marine crane onto a barge. A larger, 1000-ton crane also is at the bridge site.

Maryland Transportation Secretary Paul Wiedefield said that Tradepoint officials had agreed to allow other ships to unload vehicles at the facility's deepwater dock to be prepared for shipment to dealers.

In Oklahoma, authorities on Saturday said they shut down a portion of US highway 59 near Sallisaw after a barge struck a bridge over the Arkansas River. There were no immediate reports of injuries, according to media reports, and officials would be conducting inspections of the bridge.

Five days after the tragedy in Maryland, the jobs of some 15,000 people whose work revolves around daily port operation are on hold. While logistics experts say that other East Coast ports should be able to handle container traffic, Baltimore is the largest US port for "roll-on, roll-off" vehicle imports and exports of farm and construction equipment.

The federal government on Thursday awarded Maryland an initial $US60 million ($A92 million) in emergency funds to clear debris and begin rebuilding the Key Bridge, an extraordinarily fast disbursement.

President Joe Biden has pledged that the federal government would cover all costs of removing the debris and rebuilding the bridge.