Turkey's military returned fire against members of the Kurdish YPG militia near Syria's Afrin region overnight, broadcaster Haberturk reported early on Wednesday, citing military sources.
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.
The PKK has carried out an armed insurgency against the Turkish state since 1984 and more than 40,000 people, most of them Kurds, have died in the fighting.
Faced with turmoil across its southern border, Turkey last year sent troops into Syria to support Syrian rebels fighting both Islamic State and Kurdish forces who control a large part of Syria's northern border region.
Turkish President Tayyip Erdogan has said that Turkey would not flinch from taking tougher action against the YPG in Syria if Turkey believed it needed to.