Jakarta – Military might have staged anambush in which two American teachers were killed near the in August, AFP reported.

"The government sees three possibilities. First it could have been carried out by OPM [separatist rebel Free Papua Movement]; second, by military; or a third party which is neither OPM nor the military," said Coordinating Minister for Political and Security Affairs Susilo Bambang Yudhoyono said on Friday.

"There are indications and theories. So let the ongoing investigation continue," he said.

Gunmen opened fire on buses near the US-owned Freeport gold and copper mine in Timika on August 31, killing two US teachers and an Indonesian colleague and injuring 18 others.

Papua deputy police chief Brigadier General Raziman Tarigan earlier said that Kopassus special forces soldiers were suspected of having carried outthe attack.