Turkey shells Kurdish forces on Syria border

The Kurdish PYD and its People's Protection Units [YPG] militas have seized the key Menagh military airbase in northern Syria from anti-regime factions prompting Turkish alarm.

"The Turkish Armed Forces fired shells at PYD positions in the Azaz areas," the military source said.

There were no further details on the nature of the Turkish strikes but they probably involved artillery fire from tanks.

Turkish Prime Minister Ahmet Davutoglu had earlier warned Ankara would act if faced with a threat from across the border.

But Washington urged Ankara to halt the military strikes.

"We are concerned about the situation northern of Aleppo and are working to deescalate tensions on all sides," US state department spokesman John Kirby said in a statement on Saturday.

The PYD had also opened fire on Turkish military guard posts along the border, the Turkish military source added.

The Turkish prime minister said the shelling came in response and in line with Turkey's military rules of engagement.

Turkey considers the Russia-YPG offensive towards Azaz and the displacement of people a threat, Davutoglu added.

"We will retaliate against every step [by the YPG]," he warned.

The Turkish military has also responded to Syrian regime fire on one of its military guard posts in Turkey's southern Hatay region, military sources said.

Ankara has shown growing anger with US for backing the PYD and other Kurdish forces fighting the Islamic State group [IS] in Syria.

Turkey considers the PYD as an extension of the Kurdistan Workers Party [PKK] which it lists as a terrorist organisation against whom it has fought a bloody three-decade-long war.