"It pains me to know that we are fighting against our own people," said Moro National Liberation Front leader Habib Mudjahab Hashim. "What has happened is painful and sad and I am wondering what motivated the two to fight each other."
MNLF guerrillas and Abu Sayyaf fighters have been battling one another on the island of Jolo, with up to 26 deaths reported.
Hashim added that those involved in the clashes were legitimate MNLF members and former forces of the group that "have allied with the ASG."
Sparking the confrontation, MNLF commander Ustadz Habier Malik's forces have battled with a group led Hadji Hajari Hassan, a MNLF former leader, who has reportedly joined the ASG faction led by Raddulan Sahiron, the Inquirer Mindanao reported.
Seeking to contain the violence, the Armed Forces of the Philippines stated that the MNLF simultaneously attacked two ASG camps in Patikul, Sulu.
AFP spokesman Col. Arnulfo Marcelo Burgos said the 2nd Marine Brigade has been deployed in the vicinity to help the Philippine National Police prevent a spillover of the MNLF-ASG armed clashes, adding that government forces weren't involved in the violence.
Burgos said that four MNLF fatalities had been were beheaded by ASG members.
Second Marine Brigade commander Col. Orlando de Leon said the gun battles had caused at least 22 fatalities.
"Unverified reports indicated that both sides suffered casualties. On the side of the MNLF, reports that reached us show that eight died on their side. On the Abu Sayyaf, more or less 14 died on their side," de Leon said.
Pacification efforts may prove difficult however, as a senior MNLF field commander stated that former MNLF commander Ustadz Habier Malik is already fed up with the "un-Islamic acts of the ASG" in the province and that the ASG "bandits" should be "eliminated in the soonest possible time" to ease the situation in Sulu.
Filipino presidential spokesman Edwin Lacierda noted that the MNLF-ASG clash "is occurring in a specific isolated area" where majority of the occupants are either members of the ASG or MNLF, adding that the government's current highest priority is ensuring the safety of the civilians in the conflict areas.
Lacierda stated that while the government still has no details on why the MNLF and ASG militants were fighting, the government's highest concern was civilians caught in the crossfire.
"So right now, they are being evacuated and Social Welfare Secretary Dinky Soliman is in fact in Mindanao right now and we have identified evacuation centers already," he said. "... The civilians that have been removed in those areas are now in evacuation centers."
Lacierda said the government isn't concerned that the MNLF, which forged a peace agreement with the government in the mid-1990s, would again engage in conflict with other armed groups in Mindanao following the clash, noting that a number of amnestied former MNLF guerrillas have been given government employment.