The fighting in the town of Timika was triggered after a child from one tribe died accidentally while swimming in a river while supposedly in the care of the other, state news agency Antara reported.
Police Lt. Col. Jimmy Tuilan confirmed clashes had broken out, but gave no more details.
Timika is close to a massive gold and copper mine operated by U.S. mining giant Freeport-McMoRan Copper & Gold Inc, according to the AP.
A spokesman for the mine said the unrest was not linked to the mine and had not affected production at the site, which has been the target of violent protests in the past.
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