SAVANNAH, Ga. — Authorities said at least seven people were killed Saturday when part of a ferry dock collapsed on Georgia’s Sapelo Island, where crowds had gathered for a fall celebration by the island’s tiny Gullah-Geechee community of Black slave descendants.

Eight people were taken to hospitals, at least six of them with critical injuries, and crews from the U.S. Coast Guard, the McIntosh County Fire Department, the Georgia Department of Natural Resources and others were searching the water, according to Natural Resources spokesperson Tyler Jones. The agency operates the dock and ferry boats that transport people between the island and the mainland.

A gangway at the dock collapsed, sending people plunging into the water, Jones said. A team of engineers and construction specialists planned to be on site early Sunday to begin investigating why the walkway failed, he said.

“There was no collision” with a boat or anything else, Jones said. “The thing just collapsed. We don’t know why.”

Helicopters and boats with side-scanning sonar were used in the search, according to a Department of Natural Resources statement.

Among the dead was a chaplain for the state agency, Jones said.

There were at least 20 people on the gangway when it collapsed, he said. The gangway connected an outer dock where people board the ferry to another dock onshore.

Georgia Gov. Brian Kemp said he and his family were “heartbroken by today’s tragedy on Sapelo Island.”

“As state and local first responders continue to work this active scene, we ask that all Georgians join us in praying for those lost, for those still in harm’s way, and for their families,” Kemp said on the social platform X.

President Joe Biden said federal officials were ready to provide any assistance needed.

“What should have been a joyous celebration of Gullah-Geechee culture and history instead turned into tragedy and devastation,” Biden said in a statement. “Jill and I mourn those who lost their lives, and we pray for the injured and anyone still missing. We are also grateful to the first responders at the scene.”

Sapelo Island is about 60 miles (97 kilometers) south of Savannah, reachable from the mainland by boat.

The deadly collapse happened as island residents, family members and tourists gathered for Cultural Day, an annual fall event spotlighting the island’s tiny community of Hogg Hummock, home to a few dozen Black residents. The community of dirt roads and modest homes was founded after the Civil War by former slaves from the cotton plantation of Thomas Spalding.

Hogg Hummock’s slave descendants are extremely close, having been “bonded by family, bonded by history and bonded by struggle,” said Roger Lotson, the only Black member of the McIntosh County Board of Commissioners. His district includes Sapelo Island.

“Everyone is family, and everyone knows each other,” Lotson said. “In any tragedy, especially like this, they are all one.”