Turkish Prime Minister Ahmet Davutoğlu has blamed a lack of cooperation between opposition groups in Syria for failing to stem the advance of extremist fighters.
Davutoğlu said the people of Kobani, a Syrian Kurdish city besieged by ISIS for more than two weeks, were paying the price for the failure of the Kurdish Democratic Union Party to join forces with the Free Syrian Army.
Speaking at Wednesday night's reception to mark the start of the new legislative year in Ankara, the Turkish capital, Davutoğlu said the government contacted the Kurdish PYD and the FSA last year and told them to act together to "avert the terror threat and regime attacks in the northern belt."
He added: "If the PYD, instead of cooperating with the regime, had joined forces with the FSA and with the opposition, ISIS would not have found that much opportunity in the field."
The attack on Kobani -- just across the Turkish border -- and surrounding villages has led to 160,000 refugees seeking sanctuary in Turkey.
Davutoğlu also addressed the motions to be presented to the parliament Thursday to extend the military mandate to deal with threats from Iraq and Syria.
He said he had told Selahattin Demirtaş, leader of the pro-Kurdish Peoples' Democratic Party, not to block the motions. He also warned Republican People's Party leader Kemal Kilicdaroglu not to stand "alongside ISIS."
Turkish armed forces are currently authorized to operate across the border to defend Turkey against Kurdistan Workers' Party (PKK) fighters and the forces loyal to Syrian President Bashar al-Assad.
Thursday's session was originally scheduled to extend existing motions on Iraq and Syria that were due to expire on October 4 and 17, respectively.
PKK is listed as a terrorist organization by Turkey as well as by the U.S. and the European Union.
Turkey has launched what is publicly known as "the solution process" to end a decades old conflict with the PKK which has claimed lives of more than 40,000 people.
