HAVANA — FBI agents have arrived in Cuba to investigate the fatal shooting of five men aboard a U.S.-flagged speedboat in February that the Cuban government said was carrying suspects who were trying to infiltrate the island.

Five other men on the boat were wounded in an exchange of fire with the Cuban Border Patrol on Feb. 25 in what the Cuban government has called a terrorist attack by Cuban expatriates who had been living in the United States. The U.S. government has disavowed any connection to the group, and said it wants to fully investigate Cuba’s claims.

The FBI technical team arrived Tuesday to conduct a thorough and independent investigation, a U.S. diplomatic official who is close to the matter told The Associated Press on Thursday. The official, who spoke on condition they not be named because they were not authorized to speak publicly about the matter, did not provide details on how many FBI agents arrived or how long they would remain on the island.

Cuban President Miguel Díaz-Canel had said in March that he expected FBI agents to visit the island to help with the investigation.

Cuban officials have said the speedboat was detected with 10 men and military equipment aboard in waters north of the island. They said the men in the boat fired first and that soldiers returned fire, killing four suspects. A fifth later died from his injuries. Six other men were wounded, including a crew member in the Cuban military vessel.

The survivors face criminal terrorism charges that could carry a life sentence.

The clash occurred amid heightened tensions between Cuba and the United States.

U.S. Secretary of State Marco Rubio said at the time that the group was not a U.S. government operation, and said U.S. officials would seek to verify the information provided by Cuban authorities.

Days after the shooting, high-ranking officials from Cuba’s Interior Ministry and the Revolutionary Armed Forces displayed military equipment seized from the speedboat and confirmed they had been in contact with the U.S. Coast Guard.

The equipment included high-caliber rifles, pistols, uniforms, boots, helmets, special rations, an electric generator, a satellite communications unit and at least 12,000 rounds of ammunition.