Al-Qaeda-linked insurgent group Abu Sayyaf killed at least 19 villagers in an ambush in the Philippine town of Talipao, Sulu province on Monday.
"The [military] condemns this heinous atrocity that victimized innocent civilians. This attack cannot be justified by any ideology and shows the Abu Sayyaf’s terroristic nature," said Lieutenant Colonel Ramon Zagala of the military's public affairs office.
Brigadier General Martin Pinto, commander of the 2nd Marine Brigade based in Sulu province, said 10 militiamen and 40 civilians were caught in the ambush which occurred about 8:30 am local time.
Among the dead were 13 women and six men, while 13 others including at least four children were injured.
The villagers were traveling in two vans to visit relatives to mark the end of the Muslim fasting month of Ramadan when the incident happened.
A military source who asked not to be named said Abu Sayyaf leader Idang Susukan led the attack, one of the bloodiest committed by the Abu Sayyaf group in recent years.
"This is a retaliatory action by [Abu Sayyaf] against the militia who are supporting the military and the police in law enforcement operations," said military spokeswoman Capt. Rowena Muyuela.
"Our effort is now focused on launching pursuit operations against the lawless group," she said.
Meanwhile, on Sunday, Abu Sayyaf released a hostage after receiving US$11,500 in ransom, authorities said.
A police official, who asked not to be named, said the family and employers of kidnap victim Remigio Lingayan paid the ransom. Lingayan was kidnapped on June 5 in Indanan town, Sulu province.