MANILA - The Philippine government and Muslim rebels will sign a pact Thursday to end one of Asia's longest and deadliest insurgencies, but both sides caution much work needs to be done to secure a lasting peace.
Following 17 years of negotiations, Moro Islamic Liberation Front (MILF) leaders will sign the peace deal in exchange for control of a planned autonomous region in the impoverished south of the mainly Catholic nation.
"For many years we have been leading the Bangsamoro people's struggle and our people have gone through a lot of hardships," MILF vice chairman Ghazali Jaafar told AFP, using a local term for the Philippines' Muslim minority.
"This agreement is very important to us because this ends the fighting in Mindanao."
Muslim rebels have been battling for more than four decades for independence or autonomy in the southern region of Mindanao, which they regard as their ancestral homeland.
Tens of thousands of people have died in the conflict, while Mindanao has become one of the poorest and most corrupt regions in the Philippines.
The MILF, which the military estimates has about 10,000 fighters, is the biggest remaining rebel group yet to sign a peace accord.
Philippine leader Benigno Aquino and MILF chairman Murad Ebrahim will oversee the signing of the peace deal during a ceremony at the presidential palace in Manila.
The pact will see the two sides become partners in seeking to implement the peace deal.
The MILF chiefs would eventually order their men to give up their arms while themselves becoming politicians leading the autonomous region.
The autonomous region would comprise about 10 per cent of the Philippines' territory, have its own police force, a regional parliament and power to levy taxes. The national government would retain control over defence.
Nevertheless, the MILF, the government and independent observers warn a lasting peace is far from guaranteed, with many obstacles still to be overcome before the middle of 2016 - a crucial deadline as that is when Aquino will step down.
"Implementation will not be easy," the government's chief peace negotiator, Miriam Ferrer, told reporters, while also warning other armed groups may seek to derail the process by launching deadly attacks in the south.
Among the potential spoilers of the peace process is the Bangsamoro Islamic Freedom Fighters, a MILF splinter group of a few hundred militants that has carried out deadly attacks in the south in recent years.
The MILF leadership has committed to working with the government to neutralise the threat of the BIFF.
However, enduring distrust between the MILF and the government could yet jeopardise the peace deal.
The MILF has said it will not give up its arms or the identities of its fighters until the government fulfils its commitment to create the legal framework for the autonomous region.
Aquino needs to convince an unruly Congress to pass a "basic law" to create the Bangsamoro autonomous region. Without the law, the accord has no power.
Aquino is aiming to have Congress approve the law by the end of this year, allowing time for a plebiscite for the people in the planned autonomous region to ratify it.
Once this happens, the MILF leaders would control a transitional authority governing the region, maintaining their positions until elections are held in conjunction with national polls in 2016.
Both sides are rushing to finalise the process before the next elections because there is no guarantee that the successor to Aquino, who can only serve one term, will want to broker peace with the MILF.
Jesus Dureza, the chief peace negotiator with the MILF in 2001-2003 under a previous government, warned Aquino faced big challenges in getting Congress to pass the "basic law".
Catholic politicians from Mindanao who stand to lose power are one obvious group of potential spoilers, according to Dureza, who said Congress may seek to weaken the peace pact.
"There are influential political leaders in the area who may not look too kindly on the new (power-sharing) paradigm," Dureza said.
Various groups have also warned they may challenge the peace treaty in the Supreme Court, arguing it is unconstitutional.
Aquino has insisted the peace deal is constitutional. But he need only look back to when the Supreme Court rejected a plan in 2008 by his predecessor, Gloria Arroyo, to strike peace with the MILF, to know that his efforts could unravel.