Jakarta – The Indonesian military says it is readying its troops in case a peace agreement with rebels in Aceh province collapses.

The accord, which will be formally signed Monday in Finland, is seen as the best chance yet to end three decades of fighting that has killed 15,000 people. But several earlier accords have collapsed amid bitter mistrust on both sides.

"Basically, the Indonesian armed forces have made the necessary preparations, anticipating the worst the could happen," Indonesia's military commander Endriartono Sutarto told reporters late Tuesday.

The Indonesian army has vowed to begin withdrawing thousands of troops from the oil- and gas rich province beginning mid-September. In return, the rebels have agreed to disarm and to cease all military activities.

"If the Free Aceh Movement dissolve, the non-regular forces will no longer be necessary," Sutarto said. But he noted that the military has no way of knowing the exact strength of the rebels, and its always possible some separatists will try to scuttle the deal.

The last peace agreement collapsed in 2003, when the army kicked out foreign observers, declared martial law and arrested rebel negotiators.