The presence of Al-Qaeda-linked militants could undermine peace talks between the Philippines and the country's largest Muslim separatist force, a Malaysian-led peace monitoring mission said today.

Jemaah Islamiyah (JI) militants as well as well members of Abu Sayyaf are believed to operate in areas under the control of the 12,000-strong Moro Islamic Liberation Front (MILF).

That situation "could derail the peace negotiations," Admiral Mohammad Som told reporters Wednesday after visiting MILF areas in the the southern island of Mindanao, where the group has been waging a separatist rebellion since 1978.

The Malaysian mission, led by Som, is helping to enforce a ceasefire between the MILF and the government ahead of a final peace treaty.

Som said frequent and deadly clan wars between large Muslim families, including some MILF members, could also affect the peace process because clashes could lead to truce violations.

The JI is the Southeast Asian arm of the Al-Qaeda, while the Abu Sayyaf is a small gang thought to be responsible for the Philippines' worst terrorist attacks.

Officials in the region say the JI has been cultivating links with the Abu Sayyaf and the MILF, which has been repeatedly denied by the guerrillas.