Turkey's state-run Anadolu Agency said Turkish artillery units in the southern province of Kilis fired at Kurdish fighters in the Syrian town of Azaz in Aleppo province, saying it was in response to incoming Kurdish fire.
Turkish troops have shelled areas under the control of Syria's main Kurdish faction, the People's Protection Units, known as YPG, in the past. But Ankara appears increasingly uneasy over the group's recent gains in northern Syria.
The YPG is the main fighting force of Syrian Kurds and a key ally of the U.S.-led coalition battling the Islamic State group. Turkey, which is also in the alliance, considers it an affiliate of the Kurdistan Workers' Party, or PKK, which has waged a decades-long insurgency against Ankara.
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Akdogan says Kurdish gains in northern Syria facilitated by a Russian-backed government offensive in the same area are also putting "unacceptable" pressure on opposition-held areas in Aleppo and the nearby town of Tel Rifaat.
The private Dogan news agency broadcast footage of Turkish howitzers opening fire and shells raising plumes of smoke in Syria. It said the army hit targets in the Mannagh air base and two villages, all controlled by Syrian Kurdish fighters.
Opposition groups said Saturday that Turkish troops fired artillery shells that targeted the Mannagh air base in Aleppo province, which was captured by Kurdish fighters and their allies earlier this week.