DUBAI, United Arab Emirates (AP) — 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.

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 by the U.S. military in an apparent “friendly fire” incident on Sunday as troops continue to battle Yemen’s Houthi rebels, U.S. Central Command (CENTCOM) said in a statement.