"There was no shot fired whatsoever on the US observation post," Defence Minister Hulusi Akar said in a statement to state news agency Anadolu

He said Turkey had returned fire on Friday after Kurdish People's Protection Units (YPG) shelled a Turkish border police station from hills located one kilometre (1,100 yards) away from the US observation post in Syria.

The Pentagon said an explosion occurred "within a few hundred meters" of a US position near the Syrian town of Kobani, and warned that the US was prepared to meet aggression with "immediate defensive action".

Akar said: "All necessary precautions were taken so as not to damage the US post."

He said the Turkish forces had stopped firing "as a precaution" after the Americans contacted them.

"Anyway, the necessary coordinations are being conducted between our command centers and the Americans," Akar added.

US troops pulled back from positions along the Turkey-Syria border last week ahead of a Turkish operation against Kurdish militants in Syria.

The YPG was a close ally of the US in its fight against the Islamic State group but is seen by Ankara as a "terrorist" off-shoot of Kurdish insurgents in Turkey.