Havana, Cuba — 

An FBI technical team is in Cuba to investigate a February shootout between Cuban soldiers and the crew of a boat from Florida, CNN has learned from two sources familiar with the visit.

The rare visit by US law enforcement to the communist-run island comes amid some of the highest tensions in years between the US and Cuba and after the Trump administration said Cuban officials need to radically alter their system of government.

According to Cuban officials, a boat with 10 people aboard sailed to the island from Florida in late February to carry out “an attempt to overthrow the government.”

Upon arrival, the boaters engaged in a shootout with Cuban border guards that left four of the boaters dead and one of the Cuban soldiers wounded. A fifth boater later died of his injuries, Cuban officials said.

Cuban officials said they found a cache of assault rifles, ammunition, bulletproof vests and Molotov cocktails on the boat.

US officials said in February that at least one of those who died and one survivor were US citizens. The five survivors face terrorism charges on the island. Though Cuban officials initially identified all the men as Cuban nationals, the island’s government typically does not recognize dual nationalities and treats anyone born in Cuba as a Cuban citizen.

In March, Cuban President Miguel Díaz-Canel said FBI agents would be allowed to carry out an investigation on the island in cooperation with Cuban officials.

A US official told CNN that the American investigators are not making decisions based on information provided by Cuba but that they will independently verify what happened during the incident.

The official said that in making decisions about the case, the United States will seek to protect US interests and US citizens involved in the incident.

CNN has reached out to the FBI for comment.