JAKARTA/SINGAPORE (Reuters) - Police in the eastern Indonesian province of Papua have named six people as suspects among 17 arrested on Saturday after a violent demonstration by former mine workers at Freeport McMoRan Inc’s Grasberg copper mine, a police spokesman said.

FILE PHOTO: Indonesian police stand guard at the open-pit mine of PT Freeport's Grasberg copper and gold mine complex near Timika, in the eastern province of Papua, Indonesia September 19, 2015 in this photo taken by Antara Foto. REUTERS/Muhammad Adimaja/Antara Foto

Trouble erupted when the demonstrators blocked an access road to Grasberg, the world’s second-biggest copper mine, in a protest over employment terms. At least seven people were injured and dozens of vehicles and buildings torched, and traffic through the area was restricted amid safety concerns.

The six people were named as suspects for carrying weapons, among “various” offences, Papua Police Spokesman Ahmad Musthofa Kamal said on Monday.

“They were carrying machetes, knives and bows and arrows,” Kamal said. “This was not an ordinary demonstration.”

Under Indonesian law, naming someone as a suspect means authorities believe they have enough evidence to consider filing charges, and such cases normally go to court.

“Limited” access to Grasberg resumed on Monday, Freeport Indonesia spokesman Riza Pratama said.

Freeport has been grappling with labour problems at Grasberg as well as a lengthy dispute with Indonesia over rights to the giant mine, which has cost both sides hundreds of millions of dollars.

ABSENCE?

Following export restrictions related to a permit dispute, Freeport Indonesia, which employs more than 32,000 staff and contractors, furloughed about 3,000 workers earlier this year. This prompted a strike and high levels of absenteeism.

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Freeport has denied that there is a “formal strike”, and deemed that approximately 3,000 full-time and 1,000 contract employees who were absent had “voluntarily resigned”.

“The consequences of their actions are unfortunate,” Pratama said referring to workers’ “prolonged and unapproved absences from work despite multiple efforts and requests by the company to return to work.”

Arizona-based Freeport, the world’s biggest publicly-traded copper miner, has repeatedly said it has acted on the labour issues in accordance with Indonesian law and its labour contract, with former employees able to apply for open positions with contractor companies.

The company is in communication with worker representatives and labor unions to hear concerns and share views, Pratama said.

CONFLICT

According to Indonesian Human Rights Commission official Natalius Pigai, the former mine workers want their old jobs back and pay and all benefits to be reinstated “as before, not at different levels.”

“Freeport is committing serious violations of these workers’ rights,” Pigai told Reuters, adding that his office had recommended for the government of President Joko Widodo to intervene in the dispute and push for a joint solution.

“This affects thousands of people and has the potential to cause social conflict,” he said.

While the commission cannot impose sanctions, Pigai said his office could report the matter to the U.N. human rights council. “We won’t leave this alone.”

IndustriALL Global Union, a federation of labour unions, has also criticised Freeport’s handling of the matter, saying it treated “fired” workers “inhumanely and with contempt”.

Coordinating Maritime Affairs Minister Luhut Pandjaitan, whose office oversees the mining sector, said the government “cannot interfere” in the dispute but could make recommendations.

“It’s between (workers) and the company,” Pandjaitan told reporters.

Police are also investigating a shooting on the same access road on Thursday that injured a police officer and a search for an armed group of more than five people began in the area today, Kamal said.

Incidents like this were frequent on the access road, Kamal said.

Tensions around Grasberg could hamper Indonesia’s efforts to calm Papua, where a low-level insurgency has simmered for decades. The mine is a major source of revenue for the local economy, but its social and environmental impact is a source of friction between police and the local population.

Between 2009 and 2015, shootings within the mine project area killed 20 people and wounded 59. To protect workers and infrastructure, Freeport contributed $21 million toward government-provided security in 2015.

Freeport’s negotiations with government over its Grasberg mining permit are ongoing, Pratama said, including on the compulsory divestment of a majority stake.

“(The) four issues in the negotiations are one package deal. Divestment is one of the four issues,” Pratama said.