The tracking data shows the path of the tally container towards the bridge
A container ship collided with the Francis Scott Key Bridge near Baltimore in the early hours of Tuesday.
Several vehicles on the bridge were submerged in the waters of the Patapsco River. Hours later, the Coast Guard said at least six people were presumed dead.
Maryland Governor Wes Moore has declared a state of emergency and the Port of Baltimore is closed to ships.
President Joe Biden pledged that the federal government would cover the “full cost” of rebuilding the bridge and reopening the port.
What do we know about the bridge?
The Baltimore Bridge, more simply known as the Key Bridge, opened in 1977 in honor of Francis Scott Key, a 19th-century Maryland poet who wrote the words to the US national anthem, the Star Spangled Banner.
The bridge was 1.6 miles (2.6 km) long and spanned the Patapsco River and Baltimore Harbor. The river flows into the Chesapeake Bay, the largest estuary in the United States.
It is described as a continuous truss bridge, and its main span of 1,200 feet is the third longest of any type of bridge in the world.
Video footage of the incident showed the bridge collapsing instantly after the container ship Dally hit one of its piers. It happened around 01:30 local time (05:30 GMT) on Tuesday.
Eight people — all part of a construction crew contracted to fix and repair the sinkholes — were seen on the bridge at the time.
Two of the workers are from Guatemala, according to the country's embassy in Maryland.
Two people were pulled from the water after the bridge collapsed, one in critical condition and one uninjured, officials said.
But six more people may have died due to cold water temperatures and hours spent below the surface, the U.S. Coast Guard said Tuesday evening. The agency said it was suspending its main day-long search and rescue operation.
It will now focus on recovery efforts to find the bodies and bring closure to the affected families.
Officials say first responders were trying to find the men in treacherous conditions as there was “some cargo or retention hanging from the bridge” and dangerous debris in the water.
The water temperature in the harbor was said to be around 9C (48F). Hypothermia occurs when a person's body temperature drops below 35C.
Baltimore fire officials said the vehicles were detected by sonar in the water.
What do we know about the ship?
The Singapore-flagged container ship Daly was originally built by South Korea's Hyundai Heavy Industries for Greek shipowner Oceanbulk.
It is currently operated by charter shipping company Synergy Group and temporarily leased by container shipping company Maersk, a Maersk statement said.
Maersk added that it carried cargo to customers but no company personnel were on board at the time.
The vessel departed Baltimore's Seagard Marine Terminal at approximately 00:24 local time on Tuesday for Colombo, Sri Lanka.
Its speed steadily increased and maintained a straight course southeast along the Patapsco River.
Then at 01:25 the ship suddenly veered off its straight course and began to slow down, MarineTraffic data shows.
At this point, the video shows all the lights on the outside of the ship suddenly go out and smoke starts pouring out of the ship's funnel.
In no time it crashed into the bridge.
A mayday signal was sent as the ship approached the bridge, which gave officials time to stop cars from driving over the bridge and “saved lives,” Governor Moore said.
He said the ship was moving “very, very fast” at eight knots, or about 9 mph (15 km/h).
An unclassified memo from the US Cyber Security and Infrastructure Agency, obtained by the BBC's US partner CBS, says that Dally has “lost propulsion power”.
Synergy said all of them were Indian nationals and the two pilots, US citizens from Baltimore, were all accounted for and there were no reported injuries.
The agency said there were several possible explanations for the incident, but with two pilots involved, such an accident was unusual.
A shipping expert told the BBC that the accident could have been caused by mechanical failure, steering failure or generator blackout.
This is not the first incident involving Dali.
Dali flagged with Singapore in October 2016. According to the Maritime and Port Authority of Singapore (MPAS).
According to MPAS, certificates covering the ship's structural integrity and the operation of the ship's equipment are valid at the time of the incident.
The vessel underwent and passed two separate foreign port state inspections in June and September 2023, the authority added. During the June 2023 inspection, a faulty monitor gauge for fuel pressure was fixed before the vessel left port.
What will happen if the bridge collapses?
The location of the key bridge suggests that road traffic will be severely disrupted for months and even years. Shipping in the Port of Baltimore will also be severely affected.
The four-lane bridge was part of Interstate 695, an outer ring road around Baltimore known as the “Baltimore Beltway” and carrying 11.5 million vehicles a year.
Baltimore Harbor can still be crossed by a subway near the city, but local officials have declared a “major traffic alert” and expect significant traffic problems after the incident.
The wreckage of the bridge will be a major problem, especially for trucks carrying hazardous materials, which have been able to cross the bridge but are barred from using an alternative tunnel.
But the incident did not detract from shipping.
Transportation Secretary Pete Buttigieg declined to give a timeline for the port's closure on Tuesday, but said there would be a “huge and lasting impact on supply chains.”
Container shipping expert Lars Johnson said the incident was a “major disaster” that would “create significant problems for US importers and exporters on the US East Coast”.
At dawn the ship was caught in the remains of the bridge
“Many commercial vessels are now stuck in the Port of Baltimore,” he says, with about 21,000 units of cargo having to go through other ports in the region. None are container ships but some are bulk carriers.
Around 800,000 vehicles are estimated to have passed through the port by 2023, carrying 1.3 million tons of imported cargo.
However, while there will be some delays and additional costs, Mr Johnson says the incident will not have a significant impact from a global perspective.
