Unidentified gunmen on Friday killed a security guard and wounded three police officers at a strike-hit US-owned mine in Indonesia's restive province of Papua, police said.

He was the ninth person to be killed near the Grasberg gold and copper mine, operated by US company Freeport McMoRan, since thousands of workers went on strike over wages in mid September.

"The victim died in hospital, he had a gunshot to the head," Mimika district deputy police chief Mada Indra Laksanta told AFP. The gunmen opened fire from a nearby forest, he said.

The strike has crippled production at the mine, prompting the company in late October to declare force majeure, allowing it avoid the usual liabilities for failing to meet its contractual obligations.

Earlier this week, unidentified gunmen shot at a Freeport vehicle, wounding a contract worker.

The strikers say they are Freeport's lowest paid workers in the world and originally demanded increases of up to 20-fold, from a minimum of $1.50 to $30 an hour.

They rejected Freeport's latest 35 percent hike offer and are now calling for $4.00 an hour, to be increased to $7.50 next year.

For decades, natives of the Papua region have rejected their special autonomy status within Indonesia, demanding a referendum on self-determination for the 3.6 million population.

Indonesia took over Papua in 1969 and has since faced a low-level insurgency. Human Rights Watch says that Indonesian forces have killed civilians and imprisoned peaceful activists.

AFP