A mob demanding the closure of the world's largest gold mine today hacked three policemen and a passing air force officer to death, according to Indonesian police in Papua.

Two nearby hospitals reported at least 19 people were injured, many with gunshot wounds, in the violent protests against the mine run by Freeport-McMoRan Copper & Gold Inc, an American company.

Three policemen and one soldier were bludgeoned with rocks and knives, said police Lieutenant Colonel Paulus Waterpauw, who is leading the investigation into the attack. An earlier statement, that two of the officers had been burned alive, was retracted.

It was the third day of violent protests in the Indonesian province of Papua, a region where tensions are already running high in a separatist rebellion.

Hundreds of protesters blockaded the road outside a university in Jayapura, the provincial capital, demanding that the government close the mine. Riot police tried to break up the rally with tear gas and baton charges, but the rock-hurling students refused to move.

"The killers are no longer human beings," said police Colonel Kertono Wangsadisastra. "They went wild."

Colonel Wangsadisastra said at least five people were arrested but that members of the mob who killed the officers had fled into a nearby jungle.

Freeport’s mine is often held up by independence supporters as a symbol of the unfair division of resources between the capital and Papua, while its practice of paying soldiers to guard the facility is also deeply unpopular.

There have been several rallies against the gold mine, including one on the road leading to the mine that forced it to temporarily suspend operations, costing the New Orleans-based company millions of dollars.

"We want Freeport to close because it has not given any benefits to the people of Papua, in fact it’s made them suffer," said protester Kosmos Yual.

Sporadic clashes continued throughout the afternoon, with gunshots repeatedly heard across the city, although it was not clear who was firing. Journalists were ordered away from the scene.

Freeport defends its operations in the highlands of Papua, saying that it pays millions of dollars in taxes each year and funds scores of community projects close to the mine.

Papua’s separatist movement has been supressed by Indonesian security forces. Foreign journalists are banned from the region, some 3,700 km (2,300 miles) east of Jakarta.

Unlike Indonesia’s mainly Malay inhabitants, Papuans are ethnic Melanesians. Most Indonesians are Muslims, but Papuans are Christians or animists. Papua lies on the western side of the divided island. The eastern part of the island forms Papua New Guinea.

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