Authorities are investigating the cause of a partial ferry dock collapse on Georgia’s Sapelo Island that turned a day of celebration into tragedy, leaving at least seven dead and six critically injured as crowds gathered for a cultural festival.

The gangway collapsed Saturday as festival goers prepared to board a ferry amid Sapelo Island's annual Cultural Day, officials say.

Jacksonville Mayor Donna Deegan is speaking out about the deadly Georgia dock collapse that killed seven people, including four people from Jacksonville.