The US military says five service members were killed when their helicopter crashed into the Mediterranean Sea during a training session.
The US European Command announced on Sunday that the deadly crash occurred during a routine air refueling mission.
President Joe Biden issued a statement, saying that he is praying for the families and friends who have lost "a precious loved one." He also said, "Our entire nation shares their grief."
The US military has not provided any detailed information.
The New York Times reported on Sunday that an MH-60 Black Hawk helicopter crashed off the coast of Cyprus, citing US government officials.
It also reported that US commando teams had been secretly dispatched to Cyprus to "stand by in case they are needed to help evacuate American citizens from the region." The helicopter crew members who died were reportedly among "the aviators assigned to ferry the commandos on clandestine missions."
The US military has been allocating more of its resources to the Middle East amid the intensifying conflict between Israel and the Palestinian Islamic group Hamas.
Earlier this month, the US military announced that it had conducted large-scale joint exercises in the eastern Mediterranean.
The three-day drills involved carrier strike group members of the USS Gerald R. Ford and the USS Dwight D. Eisenhower.
The military said over 11,000 US personnel participated.