TIMIKA, Indonesia (AP) — Four Papuan independence fighters were killed in an ongoing clash between security forces and a rebel group near the world's largest gold mine in Indonesia's easternmost Papua region, police and rebels said Monday.

The clashes, which began Feb. 29 near the Grasberg copper and gold mine in Papua province, earlier killed two security personnel and injured three others. Police said the attackers are believed to be members of the West Papua Liberation Army, the military wing of the Free Papua Organization.

Rebels in Papua have been fighting a low-level insurgency since the early 1960s, when Indonesia annexed the region, a former Dutch colony. Papua was formally incorporated into Indonesia in 1969 after a U.N.-sponsored ballot that was seen as a sham by many.

Papua police spokesman Ahmad Musthofa Kamal said a joint military and police force killed four of the Papuan fighters, including a woman, in a battle with dozens of rebels armed with military-grade weapons as well as axes and arrows in Kali Bua village in Mimika district near the mining town of Tembagapura.

Kamal said security forces seized three assault rifles, five arrows and an axe during the clash. He said the rifles were identified as police weapons that had been stolen by rebels when they attacked police posts in 2012 and 2014.

Sebby Sambom, a spokesman for the liberation army, confirmed the police claim, adding that two other fighters were injured in the battle.

Attacks by rebels near the Grasberg mine have spiked in the past year.

The mine, which is nearly half owned by U.S.-based Freeport-McMoRan and is run by PT Freeport Indonesia, is seen by separatists as a symbol of Indonesian rule and has been a frequent target for rebels.

The current shootout caused about 2,000 villagers to flee for safety to neighboring Timika city.

The Grasberg mine's vast gold and copper reserves have been exploited for decades by Freeport-McMoRan, damaging the surrounding environment while providing significant tax income for the Indonesian government.

But indigenous Papuans have benefited little and are poorer, sicker and more likely to die young than people elsewhere in Indonesia.