The Philippines' main Muslim rebel group said a hardline commander blamed for some of the country's deadliest attacks in recent years had gone rogue because he opposed peace talks with the government.
Ameril Umbrakato took about 300 followers with him as he broke away from the Moro Islamic Liberation Front (MILF) and formed his own group based in farming villages of the southern Philippines, MILF vice chairman Ghazali Jaafar said.
"Until he returns to the fold he is considered a lost command," Jaafar told AFP.
"He (Umbrakato) wants us to stop the negotiations saying it is going nowhere."
The 12,000-strong MILF has been waging an insurgency for more than three decades that initially aimed for an independent Muslim state in the mostly Catholic country's south, but is now focused on autonomy.
The conflict has killed more than 150,000 people and stunted economic growth in the mineral rich but impoverished southern region.
The MILF leadership and President Benigno Aquino's government have been holding peace talks since early this year, with the next round due to be held in Malaysia next week.
Umbrakato, aged in his early 70s, organised his new group last year after giving up his command of a major MILF unit on health grounds, and has ignored repeated pleas to return to the fold, Jaafar said.
"He wants independence, which is contrary to the position of the MILF -- which is strong local autonomy," Jaafar said.
Signalling he remained a dangerous force, Umbrakato's breakaway group clashed with MILF soldiers in rural villages this month, leaving 16 people dead and forcing 3,000 civilians from their homes.
Umbrakato also led Mindanao-wide attacks by hardline MILF factions in 2008 after the Supreme Court outlawed a draft peace deal that would have given the organisation control over vast areas of the south.
About 400 people died and 750,000 were forced from their homes in that conflict.
Nevertheless, Jaafar insisted Umbrakato's group was an "insignificant force".
He said the breakaway group should not affect peace talks, but the MILF would brief the government about the developments in Kuala Lumpur on Monday.
Chief government negotiator Marvic Leonen did not return calls by AFP Friday. He has previously urged the MILF to provide details on the Umbrakato problem.
Local military spokesman Colonel Prudencio Asto told AFP the fighting between the MILF and Umbrakato's men died down nearly a week ago, and some of the 800 displaced families had started to return home.
