"Friendly fire" has killed 11 soldiers and wounded seven others in the Philippines.
The air force airstrike came as government forces tried to clear Islamic extremists from Marawi, after around 500 laid siege to the southern city for a week.
Military spokesman Brigadier General Restituto Padilla said a Marchetti S-211 jet was on a bombing run over militant positions in Marawi city on Wednesday when one bomb hit army troops who were engaged in close-range combat with the extremists.
"Despite the stringent procedure followed, there happens even with the best of armed forces, a case of friendly fire hitting our own troops," Brig Gen Padilla said.
He continued that the plane had made three successful bombing runs before the wayward airstrike.
He continued that the military had ordered an investigation.
Military Chief of Staff General Eduardo Ano said at least 25 soldiers and five police officers had been killed in clashes with the militants, along with 19 civilians.
Gen Ano continued that 89 extremists had been killed in the intense fighting, and several others had surrendered and were now providing intelligence to the military.