Manila  - The Philippines' largest Muslim separatist rebel group on Friday warned that its five-year-old ceasefire agreement with the government could collapse if stalled peace talks are not resumed soon.

Mohagher Iqbal, chief peace negotiator for the Moro Islamic Liberation Front (MILF), said the two sides must meet to extend the mandate of an international team monitoring a 2003 ceasefire in the southern region of Mindanao.

The mandate of the International Monitoring Team (IMT), which is composed of troops from Malaysia, Libya, Brunei, Canada and Japan, will expire on August 31. Malaysia already withdrew more than half of its contingent last month.

"The main mechanism of the ceasefire, the monitoring aspect, will be gone (after August 31), and it can follow that the ceasefire would collapse," Iqbal told reporters in a telephone interview. "Groups can take advantage of this vacuum and that would add to the problem."

Formal peace talks between the MILF and the government have been suspended since December 2007 over disagreements on the key issue of ancestral domain and which areas to include in a proposed Muslim homeland in Mindanao.

The two sides met in February in an attempt to revive the process, but failed to move the negotiations forward.

Iqbal said the peace talks must resume as soon as possible to settle disagreements over ancestral domain because the MILF would not discuss the IMT mandate with the government until an agreement on the issue is reached.

"We are running out of time," he warned. "Unless we discuss and finish the memorandum of agreement on ancestral domain, we cannot discuss, as far as we are concerned, the IMT."

The IMT's presence in Mindanao since 2004 has greatly decreased violence between the Philippine military and the MILF, which is the largest Muslim rebel group fighting for a separate Islamic state in the troubled southern region. (dpa)