Jayapura, Indonesia – Indonesian police have questioned 12 people in connection with deadly shootings near the giant Grasberg mine in Papua operated by a unit of Freeport McMoran Copper & Gold Inc.

Unidentified gunmen have carried out a series of attacks on a road leading to the mine in the past 10 days, killing an Australian technical expert working for Freeport, a guard employed at the mine and wounding seven policemen.

Papua police chief Bagus Ekodanto said two of the 12 people were regarded as possible suspects in the attacks.

On Monday, police found bullets and food stored along the road leading to the Freeport mine and suspect the cache could have been intended for another attack, Ekodanto said.

"We questioned 12 people yesterday, we are looking at two of them in order to develop our investigations and intend to question them further as we suspect they could be the perpetrators," Ekodanto said by telephone.

He said the two still being detained for questioning were from Timika, the nearest major town. Police had 24 hours from the start of questioning to decide whether to name the two as suspects, Ekodanto said.

The Grasberg mine has the world's largest recoverable reserves of copper and the largest gold reserves. It accounts for nearly 40 percent of Freeport's total copper reserves of 93 billion pounds, according to Freeport's website.

The mine, which is about 3,400 km east of Indonesia's capital Jakarta, has been a frequent source of friction over its environmental impact, the share of revenue going to Papuans and the legality of payments to Indonesian security forces who help guard the site.

Secessionists have waged a low-level insurgency for decades in Papua, but the Indonesian military and police who keep a tight rein on the area generally have far more fire power and have been accused by rights groups of abuses.

Freeport has said its production forecast in 2009 is 1.3 billion pounds of copper and 2.2 million ounces of gold and has said the output could still be achieved despite the attacks.

Mindo Pangaribuan, a Freeport spokesman, said in an emailed statement the road to the mine was closed for security reasons, although did not specify whether this was affecting operations.

[Reporting by Oka Barta Daud in Jayapura and Telly Nathalia and Fitri Wulandari in Jakarta; Writing by Ed Davies.]