Envoys from all 28 Nato countries are to hold a emergency meeting to discuss Turkey’s campaign against the Islamic State (IS) group and Kurdish militants.
The meeting in Brussels was called by Turkey, which has become involved in the Syrian conflict in recent days.
The country, which had previously been reluctant to intervene, has launched raids against IS in Syria and Kurdish PKK guerrillas in northern Iraq.
The strikes followed a wave of attacks by militants on Turkish soil.
Turkey, a key Nato member, called Tuesday’s meeting of the North Atlantic Council under Article 4 of the alliance’s founding treaty.
The clause allows members to request a summit if their territorial integrity or security is threatened.
It’s only the fifth time in the alliance’s history that a member state has requested such a meeting.
It will give Turkey’s Nato allies the opportunity to work out Turkey’s goals and motivation the country has stood on the sidelines fo the Syria conflict for so long, says the BBC’d defence correspondent Jonathan Beale.
It will also offer a chance to hear about US and Turkish plans to set up a buffer zone, free of Islamic state fighters, in northern Syria.
Turkey is struggling with more than 1.8 million refugees from the Syrian conflict. On 20 July IS-linked militants killed 32 people in the Kurdish-majority town of Suruc, near the Syrian border.
The crisis has exacerbated tensions in a part of Turkey where a conflict between the PKK and government troops has killed about 40,000 people since 1984.
The PKK claimed an attack which killed two Turkish police officers on Thursday. It said it was in retaliation for the Suruc bombing and what the group sees as Turkey’s collaboration with IS.
Turkish operations in Syria have also led to tensions with Kurdish militia forces fighting IS in northern Syria.
On Monday Kurdish People’s Protection Units (YPG) said Turkish tanks had shelled their positions near the Syrian town of Kobane.
A Turkish official said recent operations sought “to neutralise imminent threats to Turkey’s regional security” and were targeting IS in Syria and the PKK in Iraq.
“We are investigating claims that the Turkish military engaged positions held by forces other than [IS],” the official said.
Kurdish forces within Syria, he added, remain “outside the scope of the current military effort”.
Analysis: Paul Adams, BBC diplomatic correspondent
Turkey’s long-awaited involvement in the international coalition against IS, flying combat missions and making its vital airbases available to US jets, has been described as a possible “game changer.”
But if the government in Ankara continues to see no difference between IS and the Kurdish PKK – a position repeated on Monday by Foreign Minister Mevlut Cavusoglu – then its latest move presents the rest of the coalition, in particular the Americans, with a dilemma.
For almost a year, Kurdish rebels (the YPG, closely allied with the PKK) have represented Washington’s best hope for confronting IS on the ground in Syria.
But Turkey has no interest in promoting Kurdish success along its southern border, at a time when its own unresolved Kurdish conflict threatens to explode once more.
Turkish press fears new civil war
Officials in Washington told media that the US and Turkey were working together on military plans to clear the Islamic State (IS) group from parts of northern Syria,
They said an “Islamic State-free zone” would ensure greater stability along the Syria-Turkish border.
Under the agreement being reportedly finalised, the militants would be removed from a 68-mile (109km) stretch west of the Euphrates River, according to the Washington Post.
Such a deal would significantly increase the scope of the US-led air war against IS in northern Syria, the paper says.
Last week Turkey agreed to allow the US to use its air base in Incirlik to launch air strikes against IS.
Meanwhile Turkish police have continued to arrest suspected members of IS or the PKK, more than 1,000 over the past week.
“The Turkey-Syria border, the Turkey-Iraq border is Nato’s responsibility to protect,” Prime Minister Ahmet Davutoglu said.
“Rather than an operational decision [at Tuesday’s meeting], we are hoping all allies understand Turkey’s intentions and for them to support Turkey in its security measures when needed in the ongoing fight.”
Foreign Minister Mevlut Cavusoglu has said the PKK and its allies in Syria are the same as IS and must be eradicated.
However, both UK Prime Minister David Cameron and the US state department reaffirmed that the focus of the allied campaign in the region was fighting IS.
The week that changed Turkey
- Monday: Thirty-two people are killed by IS-linked militants in the Kurdish-majority town of Suruc, near the border with Syria
- Thursday: IS forces shoot dead a Turkish border guard
- Meanwhile, the PKK reportedly kills two Turkish police officers in retaliation for Suruc and what it sees as Turkey’s collaboration with IS
- Friday: Hundreds of suspected IS supporters are arrested and properties are searched; Turkish F-16 jets bomb three IS targets in Syria
- Saturday: Turkey strikes IS and PKK targets in Syria and Iraq; the PKK says the conditions are no longer in place to observe a ceasefire
- Sunday: Car bomb attack on a military convoy in Lice in Diyarbakir province kills two soldiers as strikes on targets in Iraq and Syria continue