The US Coast Guard says the six people missing after a bridge collapsed in the eastern state of Maryland are now presumed dead. It has suspended search and rescue operations.

Coast Guard officials said on Tuesday evening that it's unlikely that those missing are still alive, given the length of time that had passed since the accident.

A large cargo ship rammed into one of the columns supporting the bridge in Baltimore in the early hours of Tuesday. A major portion of the bridge collapsed.

The Port of Baltimore has been closed. Its entrance is being blocked by the damaged structure. The port is one of the United States' leading shipping hubs. For the past 13 years it has handled more automobile cargo than any other port in the country.

President Joe Biden held an emergency news conference on the same day. He noted that 15,000 jobs depend on the port. He said, "We are going to do everything we can to protect those jobs and help those workers."

Biden said he is sending the Army Corps of Engineers to speed up efforts to clear the channel before ship traffic can resume.

US media outlets report that in the meantime, many vessels are expected to use other ports in New York or elsewhere on the east coast, which could affect the local economy and logistics.