Farouk Arnaz – A convoy of Freeport Indonesia cars was on Saturday attacked twice on the road linking Tembagapura and the company's Grasberg mine, but no one was injured.

"A group of unidentified men shot the convoy at mile 26. The bullets hit the back windows of cars. The mobile brigadier and the Indonesian military were quick to aid the convoy. The cars, however, were shot again a second time at mile 36. Fortunately no one was hurt," National Police spokesman Insp. Gen. Saud Usman Nasution said on Monday.

Although no one has been arrested over the attacks, Saud said police and military officers were not responsible for the shootings. There has been speculation that police or military officers are responsible for the violence, intending to keep the conflicts alive in order to continue receiving pay to secure areas.

"The perpetrators couldn't be police or military officers because we've been protecting it together. It must be an armed group who didn't want Freeport to operate safely," he said.

The National Police have asked the military and local people to help solve the case because they cannot do it on their own. The police are also seeking public input for an investigation into the attack on police officer Ronald Supamena, who was shot dead by an unidentified group on the same road in February.

Ronald was killed in a shootout between police and a group of gunmen during an ambush. Concerns over the authorities' inability to halt attacks in Papua are rising.

Benny Yamato and Piter Tumoka, native Papuans who worked for a subsidiary of Freeport Indonesia, a unit of US mining company Freeport-McMoRan, were shot in February. The two men were shot in the chest while driving down a road connecting Timika and Tembagapura, but they survived. The identities of their attackers remain unknown.

The mine has been the site of arson, roadside attacks and blockades since operations began in the 1970s.