MANILA - A mortar round killed most of the 13 Marines during a clash against the Maute group on Friday, the Armed Forces of the Philippines (AFP) Western Mindanao Command (WESMINCOM) said Sunday.

“May sumabog sa kabila and then merong mortars na tumama sa posisyon ng marines, dun nagkaroon tayo ng casualty. Mortar round, pag tumama yan sa pinaka-sentro, it can create more than 11 casualties,” said WESMINCOM Commander Lt. Gen. Carlito Galvez Jr.

He said the Maute group has more knowledge on the terrain of Marawi City. Galvez added that a bridge near the site of the encounter also posed a disadvantage to government troops as they could not cross it without being exposed to sniper fire.

“Kung makikita mo rin kasi yung bridge na yun from 3 blocks papaakyat yan. So ibig sabihin nasa higher positions ang kalaban. So with that disadvantage, malaki ang possibility na magkakaroon talaga ng casualties,” he said.

So far, 58 government troops have been killed while 21 civilians and over 140 Maute fighters have died in the Marawi siege.

AFP Chief Eduardo Año however, said these are “acceptable statistics” as the Marawi siege is a “hybrid war.”

“The [Maute] do not play by the rules. They burn houses that complicated the situation,” he said.

“And in so doing, nagkakaroon tayo ng casualty particularly in sniper fires. Acceptable pa rin yung ganung statistics but of course we don’t want to lose men in fighting,” Año continued.

“And considering also the gains and successes that we have had for the last 16 to 17 days, we are really gaining and winning in this endeavor so kaunting pasensya na lang ho,” Año added.