Jakarta – The Indonesian government has ruled out extending a peace deal in war-torn Aceh province beyond December, news reports said on Saturday.

Defence Minister Mahfud M D accused rebels of using the ceasefire, officially known as a humanitarian pause, to stockpile thousands of weapons and strengthen its forces. "The humanitarian pause is extended only until December. There will be no extensions for the Free Aceh Movement," he said as quoted by The Indonesian Observer daily.

He was referring to the separatist group that has been fighting for 25 years for an independent Islamic state in the province, located on the northern tip of Indonesia's Sumatra island.

In May, government officials and representatives of the insurgents signed a three-month truce in order to enable negotiations on the future of the province of 4.1 million people. It went into effect on June 2.

The two sides have since met on several occasions in Geneva, Switzerland, but there has been no information about progress in the talks. The ceasefire has since been extended for an unspecified period.

Rebels reacted to Mr Mahfud's statement by threatening a return to full-scale war in the region. "If the humanitarian pause is not extended we will take up arms again to return the sovereignty of the Acehnese people," Abu Sofyan Daud, a Free Aceh leader in northern Aceh, said on Saturday.

While the deal has stemmed the worst of the violence, at least 87 people have been killed since its implementation. On Thursday and Friday, an upsurge in the fighting left 12 dead, including three policemen.

On Saturday, local people found the decomposed and mutilated bodies of a man and woman in Lamno in the western part of the province. At least 5,000 people have been killed in the past decade in the oil-and natural resource-rich region.