At least seven people are dead and several others are seriously injured after a gangway collapsed at a landing dock on Sapelo Island off the coast of Georgia, according to state authorities.

At least 20 people went into the water when the gangway collapsed Saturday afternoon, the Georgia Department of Natural Resources said in a statement.

In addition to the seven people who died, six people were critically injured and two others were taken by helicopter to other hospitals for treatment, said Capt. Chris Hodge, with the Georgia Department of Natural Resources, at a news conference Saturday evening.

Authorities received the first 911 call about the gangway collapse at the Marsh Landing Dock at about 3:50 p.m., according to authorities. The incident sparked a large emergency response, which included local authorities, the Georgia State Patrol and the U.S. Coast Guard. Emergency crews used boats equipped with sonar and helicopters to attempt to rescue people who fell into the water.

The cause of the collapse is still under investigation, Hodge said. An engineering and construction team was headed to the scene to examine the collapse site.

In a statement posted on X, Georgia Gov. Brian Kemp said he was heartbroken by the tragedy.

"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," he said.

Sapelo Island is located about 70 miles south of Savannah, Georgia.

The Georgia Department of National Resources manages the island, which is home to a research reserve and the Hog Hammock community, a small enclave made up of a few dozen full-time residents who are the descendants of enslaved African Americans.