Two US Navy pilots were shot down over the Red Sea early Sunday in “an apparent case of friendly fire,” the US military said.

Yemen’s Iran-backed Huthi rebels said later on Sunday they had “targeted” the aircraft carrier USS Harry S Truman a day earlier in an operation that led to “shooting down an F-18 aircraft” and thwarting “American-British aggression” against Yemen.

United States Central Command said late on Saturday that both US pilots were recovered alive but “initial assessments indicate that one of the crew members sustained minor injuries”. This incident, “was not the result of hostile fire, and a full investigation is underway,” CENTCOM said.

The potentially disastrous mistake underscores the dangers of a mission the United States has been involved in for more than a year to counter Yemen’s Huthi rebels. The Huthis have repeatedly targeted merchant vessels in the Red Sea and Gulf of Aden, waterways vital to global trade.

CENTCOM said the guided missile cruiser USS Gettysburg “mistakenly fired on and hit the F/A-18” fighter aircraft, which Navy pilots had flown off the USS Harry S Truman. US forces also shot down multiple Huthi attack drones and an anti-ship cruise missile over the Red Sea, CENTCOM said.

“The operation involved US Air Force and US Navy assets, including F/A-18s,” CENTCOM said.