By Fulya Ozerkan
Turkish tanks have shelled Kurdish-held villages in northern Syria with Prime Minister Ahmet Davutoglu warning a military campaign by Ankara could "change the balance" in the region.
With its warplanes hitting Kurdish targets in neighbouring northern Iraq again on Sunday (local time), Turkey also called an extraordinary NATO meeting for Tuesday over its cross-border "anti-terror" offensive against Kurdish separatists and Islamic State jihadists.
NATO chief Jens Stoltenberg defended Turkey's right to defend itself but told the BBC on Monday that "of course self-defence has to be proportionate".
And he cautioned Turkey about burning bridges with the Kurds: "For years there has been progress to try to find a peaceful political solution. It is important not to renounce that ... because force will never solve the conflict in the long term."
The Kurdish People's Protection Units - which pushed IS out of the Syrian flashpoint of Kobane early this year with the help of Western air strikes - said Turkish tanks hit its positions and those of allied Arab rebels in the village of Zur Maghar in Aleppo province.
The "heavy tank fire" wounded four allied rebels and several villagers, the YPG – which Turkey accuses of being allied to its outlawed Kurdistan Workers' Party – said.
It said there was later a second round of shelling against Zur Maghar and another village in the same area.
The tank fire was also reported by activists and the Syrian Observatory for Human Rights.
But Turkish officials denied the military was deliberately targeting Syrian Kurds said it was responding to fire from the Syrian side of the border.
"The bombing of the village is out of the question," a foreign ministry official told AFP. "Turkey has its rules of engagement. If there's fire from the Syrian side, it will be retaliated in kind."
Zur Maghar is on Turkish border, east of the town of Jarabulus, which is held by IS.
"Instead of targeting IS terrorist occupied positions, Turkish forces attack our defenders' positions," the YPG added.
As the bombardments were going on Davutoglu told a group of Turkish newspaper editors that Turkey's intervention would "change the balance" in the region but ruled out sending ground troops into Syria.
He denied Turkey was worried by Kurdish gains against jihadists in northern Syria.
"Why should we be disturbed? If we had been disturbed by Kurdish gains we would have been by Barzani's Kurdish region," he said, referring to the Kurdish autonomous region of northern Iraq.
Turkey has given a green light to the United States to use of its Incirlik air base to attack IS targets in Syria after months of tough negotiations.
Davutoglu declined to provide details of the agreement but said the concerns of Ankara, which had been pressing for a no-fly zone, were addressed "to a certain extent", according to the Hurriyet daily.
"Air cover is important, the air protection for the Free Syrian Army and other moderate elements fighting Daesh," he said, referring to IS by its Arabic acronym.
"If we will not send ground forces – and that we will not do – then certain elements that co-operate with us on the ground must be protected," Davutoglu added.
He ordered air strikes and artillery barrages after IS violence spilled into Turkey last Monday with a suicide bombing in a town close to the Syrian border that killed 32 people.