MANILA (Updated) -- An air force plane dropping bombs killed 11 soldiers and wounded seven others as government forces storm terrorist strongholds in Marawi City, Defense Secretary Delfin Lorenzana confirmed Thursday.
Lorenzana said it is "very sad" that the bungled air offensives, initially staged to attack Maute terror group in Marawi, instead claimed the lives of the military troops.
"Maybe the coordination was not properly done so we hit our own people," the Defense official said.
"What happened was there failure to communicate? The first attack was successful but the second one failed. We will find out," he added.
Military spokesman Brigadier General Restituto Padilla said that the Marchetti S-211 jet had made three successful bombing runs before dropping the wayward bomb that killed the 11 soldiers and wounded seven others.
Padilla assured that the military was well-trained to stage air strikes against the terrorists still holed up in Marawi City.
"Despite the stringent procedure followed, there happens even with the best of armed forces, a case of friendly fire hitting our own troops," Padilla told The Associated Press.
Lorenzana said Armed Forces of the Philippines (AFP) Chief of Staff Eduardo Ano has ordered an investigation partly to prevent another incident. Results of the probe will be out within three to five days.
The Defense official said that the bodies of the slain soldiers were already extracted from the scene and their families were contacted.
As fighting entered eighth day, government forces continue their assault on areas being occupied by the Islamic State-linked Maute Group.
On May 23, the firefight of the government forces against the Maute terror group, an Islamic State of Iraq and Syria (Isis) inspired group, ensued as the troops launched an operation to neutralize its top leader Isnilon Hapilon.
The AFP announced Wednesday that it has seized control of 90 percent of Marawi City.
President Rodrigo Duterte has declared martial law in Mindanao following clashes between government forces and the Maute group. (With AP/SunStar Philippines)