A frantic search-and-rescue effort continued on Tuesday hours after a major bridge in Baltimore, Maryland, snapped and collapsed when a container ship collided with it in the early morning, sending a number of vehicles into the water. Baltimore fire department officials said at least six construction workers were still missing, after reports that a 948ft Singapore-flagged container ship leaving port on its way to Sri Lanka had crashed into the Francis Scott Key Bridge. Jeffrey Pritzker, a senior executive at Brawner Builders, the employer of the construction workers, said Tuesday afternoon that they were presumed dead, given the water’s depth and the length of time since the crash. Pritzker said the crew had been working in the middle of the bridge when it came apart. No bodies have been recovered. “This was so completely unforeseen,” Pritzker said. “We don’t know what else to say. We take such great pride in safety, and we have cones and signs and lights and barriers and flaggers. But we never foresaw that the bridge would collapse.” A report from the Baltimore Banner earlier said the were construction workers from El Salvador, Guatemala, Honduras and Mexico who are in their 30s and 40s, with spouses and children. Officials added that up to 20 people and several vehicles had fallen into the river and declared it a “mass casualty event”. A video posted on X appeared to show the vessel striking one of the bridge’s central supports, causing much of the 2.6km bridge to give way as a number of vehicles fell into the Patapsco River below. Joe Biden addressed the bridge collapse in a public briefing about midday, saying that all indications were that it was a “terrible accident” rather than an “intentional act”. The president also said he was thinking of those who remained unaccounted for amid the search and rescue efforts around the bridge, a key traffic artery whose destruction is also expected to cause months of travel disruption in a city with more than 575,000 residents. “We’re with you. We’re going to stay with you as long as it takes,” said Biden, adding that he intended to travel to Baltimore as soon as possible. “You’re Maryland tough. You’re Baltimore strong.” Officials said the ship issued a mayday as it went off course and seemed to lose power, which Baltimore officials said allowed them to prevent more vehicles from coming on to the bridge. The ship then appeared to catch fire as part of the bridge collapsed over it, sending plumes of thick, black smoke into the air. Two people have been rescued, with one of them “severely” injured and in critical condition, officials said in a pre-dawn press conference. There were reports that there were workers on the bridge engaged in basic road maintenance when the collision occurred. The temperature in the river was about 47F (8C) in the early hours of Tuesday, according to a buoy that collects data for the National Oceanic and Atmospheric Administration. 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. “All lanes closed both directions for incident on I-695 Key Bridge. Traffic is being detoured,” the Maryland transportation authority posted on X. “I-695 Key Bridge collapse due to ship strike. Active scene,” it later added. Calls to 911 had come in at about 1.30am, reporting a vessel travelling outbound from Baltimore that had struck a column on the bridge, causing it to collapse, said Kevin Cartwright, the director of communications for the Baltimore fire department. Several vehicles were on the bridge at the time, including one the size of a tractor-trailer. “Our focus right now is trying to rescue and recover these people,” Cartwright said. He added that it was too early to know how many people were affected but described the collapse as a “developing mass casualty event”. Cartwright said it appeared that there were “some cargo or retainers” that appeared to be dangling from the bridge, creating unsafe and unstable conditions that were complicating the rescue operation. “This is a dire emergency,” he said. Matthew West, a petty officer first class for the coastguard in Baltimore, told the New York Times that the coastguard received a report of an impact at 1.27am ET. West said the Dali, a 948ft (290-metre) Singapore-flagged cargo ship, had hit the bridge, which is part of Interstate 695. The Maritime and Port Authority of Singapore (MPA) confirmed that the vessel was registered in Singapore and said the agency was coordinating with the US Coast Guard and the ship’s management company to help. It also said it would investigate the incident itself. There were 22 crew onboard at the time of the incident, Singapore said. The shipping company Maersk said that it chartered the container ship in Baltimore, with the operator named as Synergy Marine Group. Maersk confirmed that there were 22 crew, and said they were all Indian. None of them were Maersk crew or personnel. It added that there were 4,679 containers on board, roughly half of its 10,000 capacity. “We are horrified by what has happened in Baltimore, and our thoughts are with all of those affected,” the company said in a statement. The Dali had left Baltimore at 1am and was heading for the Sri Lankan capital, Colombo, according to the maritime data platform MarineTraffic. Synergy Marine Group, the manager of the Dali, confirmed that the ship had collided with one of the pillars of the bridge. It said all crew members, including the two pilots, had been accounted for and there were no reports of any injuries. “Whilst the exact cause of the incident is yet to be determined, the Dali has now mobilised its qualified individual incident response service,” it said. The same vessel was also involved in a collision in 2016 in Antwerp, Belgium, according to Vessel Finder and the maritime incident archive Shipwrecklog. Its bow reportedly scraped the side of the quay while it was leaving port, significantly damaging several meters of the hull, and it was reportedly detained by authorities afterward. According to Vessel Finder, the weather was fine at the time and the incident was blamed on the ship’s master and pilot on board. There were reportedly no injuries. The Baltimore mayor, Brandon M Scott, called Tuesday’s collision an “unthinkable tragedy” at a press conference held as dawn broke on Baltimore. “Never would you imagine” seeing the bridge collapse, he added. “It looked like something out of an action movie.” Asked how long it would take to rebuild the bridge, he said: “The discussion right now should be about the people, the lives, the souls … there are people in the water that we have to get out and that’s the only thing we should be talking about.” He and the county executive, Johnny Olszewski Jr, said emergency personnel were at the scene and rescue efforts were under way. Officials added that there was “absolutely no indication that there was any terrorism or that this was done on purpose”. The Maryland governor, Wes Moore, said in a statement that he had declared a state of emergency. He said the ship had lost power around the time when the cargo ship hit the Key Bridge, and the crew issued a “mayday” request. Moore said that officials were able to slow the flow of traffic, preventing more vehicles from falling into the water. “These people are heroes. They saved lives last night,” Moore said, adding that Baltimore was working with an interagency government team to quickly deploy federal resources from the Biden administration. Moore added the bridge was “fully up to code” before Tuesday’s accident and that rebuilding the bridge would be a long-term effort. In a statement, the White House said it was “closely monitoring” the events. “The US Coast Guard is conducting search and rescue for those who remain unaccounted for as a result of the bridge collapse,” it said. “Senior White House officials are in touch with the governor and mayor to offer any federal assistance they need. There is no indication of any nefarious intent.” It added that “our hearts go out” to the victims and families of what it called a “horrific incident”. Built in 1977, the bridge spans the Patapsco River, a vital artery that along with the Port of Baltimore is a hub for shipping on the US’s east coast. It is named for the author of the American national anthem, The Star-Spangled Banner.