Four people aboard a speedboat registered in Florida are dead after a shootout with Cuban troops in Cuban territorial waters … according to Cuba’s government.

The deadly shootout happened Wednesday morning near an island in Cuba’s Villa Clara province on the country’s northern coast … according to a statement from Cuba’s Ministry of the Interior.

Cuba says people onboard the Florida-registered speedboat opened fire against a Cuban coast guard vessel that approached them … the commander of the Cuban vessel was injured by gunfire … according to the Cubans. In addition to the four people killed, six other people on board the speedboat were wounded in the shootout.

According to the New York Times, a U.S. official says the shootout involved a U.S. civilian boat that was part of a flotilla seeking to get relatives out of Cuba.

Florida Rep. Carlos Gimenez, a Cuban-American and the former mayor of Miami, called the firefight a “massacre” and demanded an “immediate investigation” to determine if the victims were U.S. citizens or legal residents.

The Miami Herald reports Cuba’s interior ministry is investigating the incident.