Indonesia is investigating reports that more than two dozen construction workers have been shot dead by separatist rebels.

If confirmed, the killings would mark the deadliest bout of violence in years to hit Indonesia's Papua province, which has been wracked for decades by a low-level independence insurgency.

Police and military teams were sent to the scene of the alleged attack in Yigi district on Monday and came under rebel fire, leaving one soldier dead and another wounded, authorities said.

Colonel Muhammad Aidi said security forces had travelled to the area to investigate after a priest had reported that 24 workers had been "sadistically slaughtered" by an armed criminal separatist group.

"Some media are saying 31 workers are dead, some 24, so we really need to check ourselves," he added.


Image: Soldiers prepare coffins for construction workers who were reportedly killed

The construction workers were employed by a state-owned contractor, Istaka Karya, and were building bridges and road to boost infrastructure in one of the country's impoverished regions.

Work has been stopped while the investigation is carried out.

Budi Hadimuljono, Indonesia's public workers minister, said: "We're shocked and saddened to hear the media reports. All work is going to be suspended (in the area) given this incident."

Coffins were being prepared in nearby Wamena, but the operation is likely to be delayed until Wednesday morning as the military fears confrontation from rebels if they work through the night.

Image: Indonesia is investigating reports up to 31 workers have been shot dead

The violence is alleged to have started when some of the workers took pictures of the pro-Papua independence activities, angering the rebels.

But one police spokesman said they would need to check if it was definitely the separatist rebels behind the killings.

Some workers were able to escape, according to some reports.

Papua declared itself independent from the Dutch in 1961, but neighbouring Indonesia took control of the region by force two years later.

It annexed Papua in 1969 with a UN-backed vote. It now keeps a tight grip on the region.

Earlier this month, more than 500 activists were arrested in a nationwide police operation as they held rallies marking what they believe should be their independence day from Holland.

The latest incident would be the worst outbreak of violence in a "very, very long time", according to Sidney Jones, director of the Institute for Policy Analysis of Conflict, which is based in Jakarta.

She added: "Every time we have had a significant incident that has involved military deaths, even though the main victims here were civilians, it is followed by massive retaliatory response."