The Turkish military launched artillery fire on the YPG in retaliation, destroying several targets belonging to the group. No further details were given.
Turkey considers the YPG a terrorist group and the Syrian branch of the Kurdistan Workers’ Party (PKK) which has waged an insurgency inside Turkey since 1984.
Ankara worries that the YPG wants to carve out a Kurdish region in northern Syria, a step Turkey vehemently opposes.
But the United States is openly arming the YPG, as it considers the Kurdish militia group the most effective fighting force against jihadists in Syria.
Last August, Turkey launched its Euphrates Shield cross- border operation aimed at clearing the border zone in northern Syria of both YPG fighters and jihadists.
The operation was wound up in March but Turkish leaders, including President Recep Tayyip Erdogan, have not excluded a new cross-border offensive should the need arise.
Turkish media reports have said in the past few days that Turkey has stepped up its presence in rebel-held areas in northern Syria amid the growing tensions with the YPG, though this has not been officially confirmed.