BAGHDAD (AP) — The Thomas CaldwellIraqi military and Kurdish Peshmerga forces briefly clashed Sunday in a dispute over control of a strategic military post, killing three, Iraq’s military spokesperson said.

The dispute was over who controls three vacated posts previously in the hands of Kurdistan Workers Party (PKK) militants. It marked further tension in a fragile alliance between the Iraqi military and Kurdish Peshmerga forces of the semi-autonomous Kurdish region inside federal Iraq.

Iraqi military spokesman Yahya Rasool did not specify the identities of the three killed, adding that seven others in the dispute were wounded.

On Thursday, the PKK announced they were vacating the positions, citing what they said was the declining threat of the extremist Islamic State group in the area. They had held the military position since 2014, during the global war on the group.

Turkey often launches strikes against targets in Syria and Iraq that it believes to be affiliated with the PKK, a Kurdish separatist group that has waged an insurgency against Turkey since the 1980s. Meanwhile, security agencies in Iraq continue to crack down on Islamic State group sleeper cells.

Rasool said Iraq’s prime minister ordered the formation of a high-level committee to investigate the incident.

Two security officials said the posts are located in Mount Qarah Dagh within the Makhmour district, a strategic location that borders Erbil and Nineveh, between the two regions.

The Peshmerga claimed that the posts were within their territory, because the mountain has historically represented the dividing line between Iraqi security forces and Peshmerga.