At least 15 people have been killed in tribal fighting in the mountains of Papua New Guinea, reports say.
The clashes erupted in Kainantu town in Eastern Highlands province between the Agarabi and Kamano tribes.
Police said guns and knives were used in the fighting, and that a settlement was burned to the ground.
Extra troops have been sent to the area, with police warning further violence could erupt.
"It surprises everybody and I think this is the very first time we've seen a massacre or killing of that magnitude in one incident and we did not expect such a thing to occur," regional police chief Simon Kauba told Radio Australia.
He told PNG's Post-Courier newspaper that the Agarabi blamed the Kamano for law and order problems in the town.
The fighting took place on Friday, after an Agarabi group reportedly attacked a Kamano settlement known as Banana Block.
Reports said 14 of the dead were from the Kamano tribe and the settlement was burned down.
The people of Papua New Guinea speak more than 800 languages and tribal customs are fiercely protected.
Clashes between different tribes erupt sporadically: six people were killed in ethnic violence in 2008 in Western Highlands after a security guard was killed.