At least four teenagers have been shot dead in Indonesia's restive Papua province in clashes with security forces, authorities said, as human rights groups accused police of opening fire on protesters.

Monday's incident was the latest flare-up of violence in the eastern region, where poorly armed fighters have for decades been waging a low-level independence campaign for the mostly ethnic Melanesian population.

There were conflicting reports about events on Monday. Police said that four people died when several hundred protesters attacked military and police posts in the remote Madi area, in mountainous Paniai district. It was not clear who fired the shots.

But Andreas Harsono, a Human Rights Watch campaigner in Indonesia, said five high-school students aged 17 and 18 were shot dead by security forces who fired live rounds into a crowd of protesters.

It is difficult to independently verify information from Papua as Jakarta keeps a tight grip on the resource-rich region with a heavy police and military presence and there are restrictions on foreigners reporting from the area.

Police and rights activists both said tensions rose when local teenagers confronted the driver of a vehicle late on Sunday. The driver was from a local military unit, according to Harsono, and returned later with a group of people who beat up the teens.

Overnight Sunday to Monday, a local election office was set on fire and police and military posts were attacked, Papua police spokesman Sulistyo Pudjo told the AFP news agency.

"Suddenly there were victims, and we did not know who shot them," he said. "Four died, and 10 others were injured."

But HRW's Harsono provided a different injury toll, saying 21 people were wounded in the clashes, including women and children.

The police said two senior police officials as well as a forensic team were on the way to Paniai district to conduct an investigation into the violence.

Source: Agencies