Union officials say Indonesian security forces opened fire on striking workers at a U.S.-run gold and copper mine early Monday, killing one miner and critically wounding another.

Officials for the mine workers' union say violence broke out when more than 1,000 workers at Freeport-McMoran's Grasberg mine in easternmost Papua province pelted security forces with rocks.

The miners began a strike on September 15, demanding pay increases. The strike is the second at the Grasberg mine this year.

Miners walked off their jobs for eight days in July, protesting low wages and the dismissal of union leaders.