Jakarta – Many people in Indonesia's Aceh province remain traumatised two years after a peace deal ended almost three decades of war and if left untreated could trigger violence, a report said on Friday.

Some 85 percent of nearly 2,000 people interviewed in 105 villages in the province in the tip of Sumatra island were still plagued by fears and deep insecurity, a survey by the International Organisation for Migration (IOM), the Indonesian government and Harvard Medical School showed.

A peace pact between the government and the separatist Free Aceh Movement (GAM) signed in August 2005 ended a conflict estimated to have killed 15,000 people, most of them civilians.

"I would say broadly the memories of violence that occurred over those years, the memories of injustice is a potent trigger for further violence in the community," Harvard professor Byron J. Good told a news conference.

The World Bank-sponsored report said 35 percent of people interviewed appeared to be suffering from depression, 10 percent had symptoms of post-traumatic stress disorder and 39 percent showed signs of anxiety. Almost three-quarters said they had been exposed to combat, with 28 percent reporting they had suffered beatings and 38 percent that they had lost a friend or a relative in the conflict.

The limited resources of authorities remained a major obstacle to caring for mental health and short-lived programmes run by international groups were doing little to improve the situation, Good said.

The government allocated 250 billion rupiah ($27.65 million) in 2006 to compensate former rebels and help the economy. Billions of dollars of aid money poured into Aceh after the 2004 Indian Ocean tsunami devastated the province and left some 170,000 missing or dead.

But Patrick Barron of the World Bank said the aid was often not addressing post-conflict recovery. "A large part of the $9 billion aid is dedicated to tsunami recovery and very little to post-conflict rehabilitation," he said.