Turkey clashes with allies over attack on Syria Kurds

It added that the “absolute priority is the implementation of the Munich communique” - a deal to pause fighting agreed by almost 20 states at a security congress in Munich last week.

The White House said US vice president Joe Biden had made a similar appeal to Turkish PM Ahmet Davutoglu by phone on Saturday.

“The vice president noted US efforts to discourage Syrian Kurdish forces from exploiting current circumstances to seize additional territory near the Turkish border, and urged Turkey to show reciprocal restraint by ceasing artillery strikes in the area,” it said.

Brett McGurk, a US special envoy on the fight against Islamic State (IS), said on Twitter: “We have … seen reports of artillery fire from the Turkish side of the border and we have urged Turkey to cease such fires.”

Warnings of new refugee crisis

The appeals came after Turkish howitzers shelled Kurdish PYD and YPG groups in northern Syria, killing dozens of people, after Kurdish fighters, helped by Russian air strikes, seized territory including the Menagh air base near the Turkish border.

The US and EU powers see the Kurdish militias as allies in the fight against IS. But Turkey says they are a branch of the PKK, a Kurdish group designated by the US and EU as a terrorist entity, which has been fighting a 30-year insurgency against Turkish authorities.

The Turkish leadership has refused to back down.

Davutoglu told German chancellor Angela Merkel over the phone on Sunday that his forces "gave the necessary response and will continue to do so", according to his office.

He added that the PYD-YPG offensive was aimed "not just at Turkey but also the European Union" and that it would prompt a “new wave of hundreds of thousands of refugees” from Syria.

Turkish foreign minister Mevlut Cavusoglu, speaking in Munich to the Sueddeutsche Zeitung daily, urged the US and EU to back safe zones for refugees inside Syria if they wanted to stem the flow of people.

Turkey’s deputy PM, Yalcin Akdogan, told the Kanal 7 TV broadcaster: "Turkey is not a nation that is going to sit down and watch everything from the sidelines or the stands.

"The YPG crossing west of the Euphrates is Turkey’s red line."

The comments follow strident words by Turkish president Recep Tayyip Erdogan last week, who told the US: “Are you together with us, or are you with the PYD and YPG terror groups?

"Allies don't tell each other: 'My enemy's enemy is my friend’."

Persuading Assad

US president Barack Obama also spoke over the phone to Russian leader Vladimir Putin on Sunday.

“President Obama emphasised the importance now of Russia playing a constructive role by ceasing its air campaign against moderate opposition forces in Syria,” the White House said.

The Kremlin version of the conversation said it focused on “the importance of establishing a common counterterrorist front and renouncing double standards”.

The swirl of appeals and refusals comes after a group of almost 20 states, including EU powers, the US, Russia, and Turkey, agreed in Munich on Friday to a “cessation of hostilities” in Syria in one week’s time.

But the accord says strikes can continue on “terrorist” entities, with Russia claiming that all of its strikes are hitting IS and other radical groups such as Jabhat al-Nusra.

“The task now is that Moscow and Tehran bring the Assad [Syrian] regime to lay down their arms,” German foreign minister Frank-Walter Steinmeier told press at the time.

“Whoever doesn’t cooperate ... must reckon with all the consequences for refusing,” he said.

The UK’s Philip Hammond said the deal would only work if there was “a major change of behaviour” by Russia.