It was not clear whether there were any casualties. Turkish officials could not immediately be reached for comment on the report, which said Turkey’s military retaliated after YPG fighters opened fire on their positions. Afrin is in northwest Syria and near the border with Turkey.
The United States supports the YPG in the fight against Islamic State in Syria, despite repeated protests from NATO ally Turkey, which sees the Syrian Kurdish fighters as terrorists and fears their advance will inflame a Kurdish insurgency at home.
Turkey was angered by a U.S. decision last month to arm the YPG as part of the battle for Islamic State’s Syrian stronghold of Raqqa. Ankara considers the YPG as an extension of the Kurdistan Workers Party (PKK), which is outlawed in Turkey and is also considered a terrorist group by the United States and the European Union.