It was the first major incident between the two since December 2009, when Iran took control of a disputed oil well.
The gunfight lasted 90 minutes and an Iraqi officer was captured.
On April 10, 2006, seven PJAK members were arrested in Iran, on suspicion that they killed three Iranian security force personnel.
Shortly afterward, on April 21, and again a week later, Iranian troops fired nearly 100 artillery shells at PJAK positions near Mount Qandil and briefly crossed the Iraqi border, according to the Iraqi Ministry of Defense.
According to Hiedelberg Institute for International Conflict Research, the attack, which occurred on April 24 and 25, involved PJAK attacks on two police stations in the cities of Ravansar in northern Kermanshah province and in Sanandaj, the capital of Kordestan province, killing eleven police officers, with more than ten PJAK members reportedly killed.
Two Kurdish guerillas affiliated to PJAK were reported to had been killed and another wounded by the IRIB TV website on June 19, 2011, in Iran's northwestern town of Chaldran in West Azerbaijan province.In August 2008, under Iranian pressure, one of Iraqi Kurdistan's ruling parties, the PUK, launched an offensive against PJAK forces.KDP-leader and President of Iraqi Kurdistan, Massoud Barzani condmened PJAK operations against Iran multiple times.In 2010, PJAK claimed responsibility for the deaths of 3 Revolutionary Guard soldiers in Khoy.Earlier in the year Iranian police arrested a suspect in the killing of a prosecutor in the same region during clashes with "Kurdish militants." On , Iraqi and Iranian border guards exchanged gunfire near the border village of Shamiran, after the Iranians mistook the Iraqis for members of PJAK.Discouraged by the failure of previous Kurdish revolts, however, PJAK's leaders initially worked only to maintain and build a Kurdish national identity and to thwart the Iranian government's attempts to re-brand Iranian Kurds as ethnic Persians or Aryans.Once established at Qandil and operating under the PKK's security umbrella, PJAK adopted many of the political ideas and military strategies of jailed PKK leader Abdullah Ocalan, whose theories had initially inspired PJAK's founders while still in Iran.PJAK claimed 21 Iranian soldiers were killed in the clashes.During clashes in the Jasosan and Alotan heights the next day, Iranian forces claimed to have killed over 21 PJAK fighters, confirming that two Revolutionary Guards had been killed and two had been injured during the clashes.PJAK is suspected to be closely affiliated with the Kurdistan Workers' Party operating against Turkey.Following massive clashes in summer 2011, a cease-fire was declared between the parties, with Iran claiming victory and PJAK allegedly ending all armed operations as of 29 September 2011.