 The Patriotic Revolutionary Organization of Bethnahrin was formed in the 1990s by Assyrian-Syriac nationalists who previously fought within the PKK against Turkey.The group carried out its first attack alongside the PKK against a Kurdistan Democratic Party (KDP) military compound in the town of Kasre on 17 July 1999, where 39 KDP Peshmerga fighters were killed and 20 injured.Three days later a second attack was carried out by the group in which several of Massoud Barzani's fighters were killed when an army truck driving on a bridge between Kasre and Haci Umran was blown up by the PROB.