Two men were killed and about 20 were injured Saturday when police opened fire on demonstrators during a rally in Indonesia against a proposed gold mine, authorities said.

About 800 police were deployed to disperse several hundred demonstrators who had been occupying a port in West Nusa Tenggara province since early this week, said National Police spokesman Saud Usman Nasution.

"The protesters turned violent. They threw Molotov cocktails and stones at police. There was no option but firing on them," he told AFP, adding that 20 people were also injured in the violence.

"For the sake of public interest ahead of Christmas and New Year celebrations, we have to take action against [demonstrators] as the port activity was totally paralyzed these past few days," the police spokesman added.

The Sape port is the main gateway to Flores, a neighboring island in eastern Indonesia.

Local broadcaster MetroTV aired images of anti-riot police firing on protesters and using water cannons to break up the crowds. Police said they seized petrol bombs and other weapons, including a dozen machetes and sickles.

At least 36 people were arrested "for questioning," including six children and five women, the spokesman said, adding that the port resumed normal operations Saturday afternoon.

Local officials recently granted an exploration permit to miner Sumber Mineral Nusantara, despite criticism over the proposed gold mine's ecological impact.