At least one person was killed and several others injured when a boat collided with a ferry near Clearwater, Florida, officials said Sunday night. The exact number of injuries was not immediately known, but the fire department declared it a mass casualty incident, the Clearwater Police Department said. Six people were declared "trauma alerts," the city of Clearwater said, and two of those who were "more seriously injured" were taken away by helicopter, police said. According to police, a Clearwater Ferry carrying 45 people, including two crew members, was hit by another boat, which fled the scene of the crash. The other boat, a private recreational vessel that was carrying six people, has been identified, the Coast Guard said. The ferry "came to rest on a sandbar just south of the Memorial Causeway bridge," police said. All the passengers, including those who were injured, have been taken off the ferry. The Clearwater Memorial Causeway bridge connects Clearwater and Clearwater Beach.