The Cuban government says its forces have shot and killed four people on a US-registered speedboat that entered its waters and opened fire on a patrol boat.
It added that six others on the speedboat were injured.
The Cuban commander of the border patrol boat was also wounded, according to Cuba‘s interior ministry.
It said the injured were evacuated and are receiving medical attention.
In a later statement, the ministry said that the 10 passengers on the speedboat were Cubans living in the US and that “according to preliminary statements by those detained, intended to carry out an infiltration for terrorist purposes”.
It added that all 10 were armed and the majority “have a known history of criminal and violent activity”.
The ministry named the six people detained as Amijail Sanchez Gonzalez, Leordan Enrique Cruz Gomez, Conrado Galindo Sariol, Jose Manuel Rodríguez Castello, Cristian Ernesto Acosta Guevara, and Roberto Azcorra Consuegra.
It added that Amijail Sanchez Gonzalez and Leordan Enrique Cruz Gomez are wanted by Cuban authorities “based on their involvement in the promotion, planning, organisation, financing, support or commission of actions carried out in the national territory or in other countries, in connection with acts of terrorism”.
The ministry also named Michel Ortega Casanova as among the deceased and said efforts were under way to identify the remaining three individuals.
US secretary of state Marco Rubio said no US government personnel were involved but insisted: “We are going to have our own information on this, we are going to figure out exactly what happened.”
He said US would try to determine if those in the incident were US citizens or permanent residents but said he was not “going to speculate about whose boat it was, what they were doing, why they were there, what actually happened”.
The Florida-registered speedboat came within one nautical mile of a channel on Falcones Cay, on Cuba’s north coast, when it was approached by five members of a Cuban patrol unit, the interior ministry also said.
The crew of the speedboat then opened fire, wounding the commander of the Cuban vessel, the statement added.
Florida‘s attorney general James Uthmeier said he was ordering prosecutors to open a separate investigation with other state and federal law enforcement partners.
“The Cuban government cannot be trusted, and we will do everything in our power to hold these communists accountable,” he wrote on X.
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Florida congressman Carlos Gimenez, a Cuban-American former mayor of Miami, demanded an “urgent” investigation into what he called a “massacre”, adding US authorities “must determine whether any of the victims were US citizens or legal residents”.
“This regime must be relegated to the dustbin of history!” he wrote on X.
“Faced with the current challenges, Cuba reaffirms its commitment to protecting its territorial waters, based on the principle that national defence is a fundamental pillar for the Cuban state in safeguarding its sovereignty and stability in the region,” the interior ministry statement said.
It comes amid a time of heightened tensions between the US and Cuba following increased pressure from Donald Trump’s administration.
The two countries previously collaborated on combating drug smuggling and other crimes, but have ceased to do so.
The US has also blocked virtually all oil shipments to the island, piling pressure on its Communist-run government.