The shootout, which killed four of 10 people allegedly trying to infiltrate Cuba with terrorist intent, comes as the U.S. has choked off Cuba’s oil supply and raised the possibility of regime change.

Cuba's Interior Ministry said Wednesday night that the boat was carrying 10 people armed with assault rifles, handguns and Molotov cocktails.

Aboard the Florida-registered vessel, four were killed and six wounded, Cuba said. Secretary of State Marco Rubio said U.S. personnel were not involved and called for an investigation.

Four armed Cubans aboard a Florida-based speedboat died in a gunfight with Cuban border troops on Wednesday, officials said.

Cuba says the 10 passengers on a boat that opened fire on its soldiers were armed Cubans living in the U.S. who were trying to infiltrate the island and unleash terrorism

Cuba said its forces fatally shot four heavily armed people attempting to “infiltrate” its territory on a Florida-registered speedboat on Wednesday, amid simmering tensions between the communist island and the US.

Cuba says it thwarted armed exiles on a Florida-registered speedboat who were trying to infiltrate from the US

A U.S. registered speedboat violated Cuban territorial waters, kicking off an armed confrontation with Cuban border guard troops in which four people were killed, Cuban officials said.

The incident comes at a time of heightened tensions between Washington and Havana.

Historical conflicts between the US and Cuba span six decades and include Cuban Revolution, Bay of Pigs invasion and the Cuban Missile Crisis.