Syrian Kurdish forces of the Democratic Union Party (PYD) that are fighting Islamic State militants say Turkish tanks continued shelled villages under their control late Sunday, saying the attacks occurred west of the Syrian town of Kobani.
A Turkish Foreign Ministry statement denied the attacks.
Turkish political columnist Semih Idiz says if true, the situation is damaging for Ankara.
"It would be dire because the Syrian Kurds are currently allies to Turkey’s Western allies," Idiz said. "People would start questioning what Turkey’s priorities are here."
The PYD, with the support of NATO air strikes, has in the past few months inflicted a series of defeats on Islamic State militants, capturing large swathes of territory along Turkey’s border.
But Ankara accuses the PYD of being affiliated with the Kurdistan Workers' Party (PKK), a group of Turkish Kurds that has been fighting the Turkish state for decades for greater minority rights.
Idiz says Ankara is deeply suspicious of the PYD.
"They are afraid that the PYD will organize itself like the Iraqi Kurds after the first Gulf War and establish an autonomous region along Turkey’s border with Syria," he said. "And they also see the links between the PYD and PKK and feel this will have a spillover effect in Turkey and encourage Kurdish separatism in Turkey."
Carnegie Institute visiting scholar Sinan Ulgen says the decision last week by Ankara to join the anti-IS coalition in air strikes against the jihadists is a bid to build international support to contain the PYD.
"Turkey [has] now decided to be a more active partner in the anti ISIS coalition to be able to receive more support politically in its aspirations to contain PYD expansionism in the region."
At the request of Turkey, NATO ambassadors have called an emergency session for Tuesday to assess the threat IS extremists pose to Turkey, and discuss the response of Turkish authorities.
The alliance said the meeting was requested "in view of the seriousness of the situation after the heinous terrorist attacks in recent days."
A White House spokesman said Sunday Ankara was within its rights to "take action related to terrorist targets," including when it struck the PKK town overnight Friday in northern Iraq, marking the first offensive against the outlawed Kurdish group there since a peace accord was announced in 2013.
