Palu. At least two people have died in violent clashes between local employees of a nickel mining company and their Chinese employers after the union forced workers to go on strike in the Central Sulawesi district of North Morowali, police said on Sunday.

Hundreds of officers were deployed to restore order at Gunbuster Nickel Industry after workers burned heavy machinery and vehicles during the riot that occurred on Saturday evening.

Police said 69 people were arrested for provoking workers into violent protests and destroying the company’s properties. The identities of the deceased have yet to be determined.

"We are working to identify the deceased – a local worker and a foreigner – and investigating the cause of their deaths,” Central Sulawesi Police Chief Insp. Gen. Rudy Sufahriadi said in a news conference in North Morowali.

The clashes also left nine workers seriously injured and are now being treated at a local hospital.

"We must admit that our force was at the minimum but we already brought in reinforcement. We are evaluating the incident and hopefully, we can prevent a recurrence," the police chief said.

The incident began on Saturday morning when hundreds of workers staged a rally after negotiations over better work conditions and wages couldn’t reach a settlement. 

They forced other workers to go on strike and began to attack those who continue to work and vandalize buildings and equipment.

"They forced their way into the building and intimidated their colleagues who continued to work," Central Sulawesi Police spokesman Chief Comr. Didik Supranoto said.

Police personnel were at the scene to control the mob but they were outnumbered and could do little when the rally turned violent as angry workers set buildings and equipment on fire and looted offices.