Turkish troops are continuing to shell positions of the YPG in Syria’s Azaz district located in the northern countryside of Aleppo, Turkish security sources said on Sunday.
Turkey started to strike YPG targets near the town of Azaz in northern Syria on Saturday after YPG militants had shelled a former military air base near the Turkish border.
Turkey views the group as the Syrian extension of PKK terrorist organisation.
PKK terror attacks have claimed the lives of more than 300 security officials and several civilians since July 2015 when it resumed its 30-year armed campaign against the Turkish state, after unilaterally ending a two-year ceasefire.
The YPG controls nearly all of Syria's northern frontier with Turkey.
Turkish Prime Minister Ahmet Davutoglu said on Saturday that the shelling had taken place under "the rules of engagement against forces that represented a threat in Azaz and the surrounding area".
Davutoglu said that the government warned the group many times to withdraw from the area, which has recently been captured, however it chose to violate the Turkish territory, shelling military outposts near the Turkish border.
"We will retaliate against every step [by the YPG]," Davutoglu told reporters during a televised broadcast.
"The YPG will immediately withdraw from Azaz and the surrounding area and will not come close to it again."
Davutoglu demanded that the Menagh base be evacuated and said he had spoken to US Vice President Joe Biden to make that point and stress that the YPG was an extension of the PKK and a direct threat to Turkey.
Davutoglu also said "When there is any threat to Turkey, we will take the measures we took in Qandil in Iraq and in Syria as well and will not hesitate to implement any necessary measures."