The terrorist PKK's Syrian affiliate PYD and its armed wing YPG are hired soldiers of Russia since they fight moderate opposition forces instead of Daesh, the Turkish premier has said.
Addressing his ruling Justice and Development (AK) Party MPs at the Turkish parliament in Ankara on Tuesday, Turkish Prime Minister Ahmet Davutoglu said: "Neither Daesh nor YPG are primary components of these territories.
The YPG and the PYD are legionnaires [and] hired soldiers of Russia". In Washington, the State Department denied that Russia and the YPG have been cooperating in Syria.
"We've seen no connection whatsoever," spokesman Mark Toner told reporters.
He reiterated Washington's calls for Turkey to halt cross-border shelling, while urging the YPG to "stop its own actions on the ground that we believe raises tensions."
The Turkish military has been shelling PYD and PKK positions in northern Syria for three consecutive days in retaliation to artillery fire from PYD forces based around Azaz town, located in Aleppo’s northern countryside, Saturday night.
The exchange of fire came after YPG's recent advance into Azaz, which has been the scene of recent heavy fighting, just six kilometers (four miles) from the Turkish border.
About the YPG attack on Turkey, he said the "latest attacks obviously targeted Turkey and threatened its border security".
"Turkey will continue to retaliate whenever and wherever it is necessary in order to protect its own borders [and] prevent an ethnic cleansing that poses threat for its security; [it will not] allow any further human tragedy or intense refugee flow, and [it will] prevent the weakening of Syrian opposition forces," he added.
Davutoglu reiterated that Ankara regards the PYD and the YPG not as Kurdish groups, but as terrorist organizations since they are Syrian extensions of terrorist PKK.
"PYD and YPG are puppets of Russia and subcontracted organizations used by the 'blood-spiller Assad regime' and Russia," he said.
The Turkish premier noted that Moscow and Assad regime were displacing thousands of people by using the PYD in order to change the ethnic demographic nature of Syria's north and by allowing a certain demography to exist in Aleppo that is dominated by pro-regime elements.
Turkish premier further said that the PYD was fighting Syria's moderate opposition under the pretext of battling Daesh.
"Gaining legitimacy from the international community under the pretext of carrying out an anti-Daesh fight, Russia and PYD aim at empowering the Assad regime by attacking only anti-Assad groups without any single assault on Daesh," he said.
"Ethnic cleansing has been carried out on all anti-regime opposition groups not affiliated with Daesh so as to clear them out of Syria," Davutoglu added.
He said Turkey's recent shelling and operations have halted YPG's advance in Azaz.
Davutoglu also touched upon the intensified Russian aerial offensives on northern Syria, saying Russian fighter jets were randomly shelling bombs over the area without distinguishing between civilians and the military.
"Russian warplanes are not only using smart bombs but they are shelling all their bomb stocks without thinking or estimating where they hit since they are trying to use up their expired bomb stock in their inventories," he said.
The premier added that Russian jets conducted 200 such sorties over the little town of Azaz on Monday alone.
U.S. President Barack Obama said Russia would involve itself in a quagmire in Syria by propping up Assad, which continues to result in a massive refugee outflow and bombing of schools and hospitals where hundreds of civilians continue to die.
Adding the ongoing crisis in Syria was "not a contest" between him and Russian President Vladimir Putin, Obama said it would be "pretty costly" and "a big piece of business" for Russia if Putin thinks he could prepare "to invest in a permanent occupation of Syria with Russian military".
"If you look at the state of the Russian economy, that's probably not the best thing for Russia," he said.
"What would be smarter would be for Russia to work with the United States and other parties in the international community to try to broker some sort of a political transition."
The president also stressed that Russian involvement in Syria did not "distract" the U.S. from continuing to focus on Daesh and that the U.S. continued to press militants in Iraq and Syria.
"That will not stop," he said.
Last week, the YPG, with Russian air cover, began a massive offensive aimed at capturing opposition-held areas of the Aleppo countryside.
In recent days, the group managed to seize control of several villages and a military airport in the area. Monday saw Russian warplanes targeting two schools and a hospital in Azaz; another hospital in Idlib managed by Geneva-based Doctors Without Borders was also hit that left more than 30 people, including women and children dead.
Turkish Foreign Ministry issued a statement to strongly condemn the Russian offensives, calling them an "unconscionable and obvious war crime under international law". "If the Russian Federation does not end those attacks immediately, which removes peace and stability, it is inevitable that Russia will face bigger and more serious results," the statement added.
UN human rights spokesman Rupert Colville also told a news conference on Tuesday: "If it was deliberate, intentional targeting of those facilities, it could amount to a war crime".
Syria has remained locked in a vicious civil war since early 2011, when the regime of President Bashar al-Assad cracked down on pro-democracy protests with an unexpected ferocity.
Since then, more than 250,000 people have been killed and more than 10 million displaced, according to UN figures.