Seven people are believed dead after a gangway that's part of a marina collapsed on Sapelo Island, Georgia, on Saturday.
Georgia's Department of Natural Resources said at least 20 people went into the water when the structure gave way before 4:30 p.m., prompting a response from the U.S. Coast Guard and state and local agencies.
The number of injured and the extent of their injuries was unknown, the agency said.
"Georgia DNR and multiple other emergency agencies deployed boats, equipped with side-scan sonar, and helicopters for search and rescue missions," it said. "The gangway has been secured on Sapelo Island and the incident is currently under investigation."
According to the department's background on the gangway, it's used by public ferry vessels, the University of Georgia's research trawler, and some small boats.
The Sepalo Island Cultural and Revitalization Society organized its annual Cultural Day celebration on the island on Saturday, calling it "our most celebrated event." It's not clear if celebrants were on the gangway.
Sapelo Island, on the Atlantic Coast, is about 72 miles south of Savannah.
This is a developing story. Please check back for updates.