(NewsNation) — Recovery operations following the massive bridge collapse in Baltimore have been a “remarkably complex mission,” Democratic Maryland Gov. Wes Moore said during a Thursday appearance on “CUOMO.”

President Joe Biden is set to visit Maryland on Friday as crews work on clearing the wreckage from the collapse of Francis Scott Key Bridge in Baltimore.

“We have 27,000 tons of bridge debris that’s also now sitting pancaked at the bottom of the river,’ Moore said. “And there are four souls that are still unaccounted for.”

Two workers survived, two bodies were found in a submerged pickup and four more men are presumed dead after a container ship plowed into the bridge. Authorities have said the ship lost power. An investigation to better understand the situation is underway.

“I can’t overstate the level of devastation that this collapse has had,” Moore said. “It’s really unprecedented when you have a ship that is literally the size of the Eiffel Tower and the weight of the Washington Monument that is now sitting trapped in the middle of the Patapsco River.”

The bridge spanned 1.6 miles across the river. Biden has said the federal government will pay the full cost of rebuilding the bridge. His administration approved $60 million in immediate aid last Thursday.

“This is a remarkably complex mission and operation, where we continue both to pray for the families and work to bring them a sense of closure.”

Opened in March 1977, the bridge was a connecting point for the Charm City and the final link for the Baltimore Beltway (Interstate 695), according to the Maryland Transportation Authority.

More than 12.4 million vehicles crossed the bridge in 2023, according to a Maryland state government report.