A U.S. missile cruiser shot down a Navy fighter jet in what military officials said was a “friendly fire” incident over the Red Sea on Sunday, as the U.S. military has increased its presence in the Red Sea to fight back against Iran-backed Houthi rebels in Yemen.

Two US Navy pilots ejected safely after their fighter jet was shot down over the Red Sea on Saturday in an apparent friendly fire incident, US Central Command said in a statement.

Two U.S. Navy pilots were shot down Sunday over the Red Sea in an apparent “friendly fire” incident, the U.S military said, marking the most serious incident to threaten troops in over a year of America targeting Yemen’s Houthi rebels.