That came as the death toll from Thursday's clashes rose to five and tensions remained high.

Witnesses said Friday sporadic gunfire was heard in the streets of Jayapura in which three policemen and an air force officer were beaten to death.

A man aged around 40 also died of head injuries in Jayapura's main hospital Friday morning. Hospital director Pauline Watufa said the man had suffered serious head injuries. Fifteen other people, including six police personnel, were being treated for gunshot wounds and head injuries, she said.

There are fears the latest violence could trigger further unrest in the isolated province, some 3,000 kilometers east of Jakarta, where Indonesia has grappled with a sporadic separatist conflict for decades.

The huge Timika gold and copper mine run by US giant Freeport-McMoRan has come to symbolize local grievances with Jakarta.

President Susilo Bambang Yudhoyono has condemned Thursday's "anarchic action" while ordering an investigation into Freeport's activities. The US-based Human Rights Watch demanded an independent probe into the bloodshed.

Papua police spokesman Kartono Wangsadisastra said the 57 people were arrested in connection with clashes, which saw about 1,000 rock-throwing protesters facing off with armed police near the city's state-run university.

"We will never stop hunting these people who have created havoc and murdered our officers," he added.

Wangsadisastra said the situation in the town had largely returned to normal and that police were patroling the streets unarmed. But Obet Rawar of rights group Elsham-Papua said gunfire was heard around the city in the morning as riot police fired into the air.

According to resident Johannes Do, police were firing as they escorted the bodies of their slain comrades to the airport. "They shot to the left and right as they traveled all along the street" leading away from the university, Do said.

The violence has shaken the government in Jakarta. The head of the armed forces, the national police chief and the nation's top security minister held talks in Jayapura with community leaders in the mainly Christian region to ease tensions, Wangsadisastra said. The officials urged the community leaders to give sermons calling for peace.

Thursday's bloodshed was the climax of weeks of rallies over the world's largest gold and copper mine, which is a top source of revenue for the Indonesian government. Freeport-McMoRan has been accused of not giving enough to the people of Papua in return for the mine, causing pollution and being responsible for human rights abuses through their use of the military for protection.

Freeport said it would "continue its efforts to ensure that the local people of Papua will share in the economic and social benefits resulting from its operations." The company currently gives 1 percent of annual profits to seven tribal groups living near the mine.

Jayapura is more than 400 km northeast of Timika, where the mine is located. There, a company spokesman said there had been "no disruption whatsoever" to operations.

Yanke Baru, a member of the Elsham-Papua group, said Thursday's violence flared when police assaulted a student leader during the anti-Freeport, anti-Jakarta demonstration.

The students had gathered outside the university, blocking a main road and demanding the closure of the mine. "The students were insulting Indonesia, yelling `Indonesia is a robber, Indonesia protects Freeport,"' said Benny Giay, a local Christian minister.

"Then the mass started throwing stones while police were negotiating with a student leader. The police grabbed the student leader, and when other students saw police treat him so brutally they threw many stones. And that's when police started beating some students," Baru said.

The situation degenerated quickly, Baru said, with police officers being beaten and their comrades opening fire.

Some authorities said the officers had fired rubber bullets and blank rounds, but Baru said "they used live bullets. I took 12 students injured to the [hospital]. Ten students were shot." AGENCE FRANCE-PRESSE