MANILA, Philippines -- Philippine officials have signed a power-sharing accord with the country's largest Muslim rebel group and expect to sign a final peace pact with the insurgents next month to end a decadeslong rebellion in the volatile south.

The accord, which outlines the powers of a Muslim autonomous government in a region to be called Bangsamoro, was signed Sunday by negotiators for the government and the 11,000-strong Moro Islamic Liberation Front in Malaysia, which has been brokering the talks, officials said Monday.

The accord is the third of four proposed pacts that are to constitute a final peace agreement between the government and the Moro guerrillas. The insurgents have been fighting for self-rule for minority Muslims in the south of the predominantly Roman Catholic nation in an insurgency that has left thousands of combatants and civilians dead and held back progress in some of the country's poorest regions.

President Benigno Aquino III said the remaining accord to be tackled next month, involving rebel disarmament, is expected to be difficult because it entails the insurgents relinquishing their arms.

"This is a heavy and contentious issue for them because if they undertake this act, it would mean an extreme demonstration of their trust to our government and country," Aquino told reporters.

The power-sharing accord would allow minority Muslims to rule a more powerful autonomous region through a 50-member assembly to be led by a chief minister. The Philippine government would retain authority over areas such as defence, foreign and monetary policy, postal service and immigration, according to a copy of the pact.

The autonomous government would wield exclusive power over such areas as agriculture, trade, tourism and education, and could contract loans and establish free ports, it said.

The United States and other governments have backed the peace talks, hoping they will turn battlefields into prosperous communities and economic growth hubs instead of breeding grounds for Muslim extremists who could create trouble in the country and elsewhere.

However, at least three smaller armed groups oppose the current peace talks. Moro rebels from one group took scores of hostages in September and occupied coastal communities in southern Zamboanga city in a bloody siege they launched after accusing the government of reneging on its commitments under a 1996 peace pact.

Thousands of troops ended the weekslong uprising with a major offensive that killed more than 200 people, most of them insurgents.

While the talks were underway in Malaysia last week, a group of Muslim rebels stormed a police station in the southern Philippines, briefly held a city police chief hostage and shot and killed a civilian in an apparent attempt to release some detained comrades.

Government negotiator Miriam Coronel-Ferrer said cease-fire officials were dealing with the incident, which underscored the difficulty of forging peace in the country.

"We have always said that the road ahead is going to be rough," she said.