NATO ambassadors are gathering for an extraordinary session after Turkey called the meeting about security concerns. Earlier, Ankara and Washington agreed to drive "Islamic State" fighters from northern Syria.
NATO Secretary General Jens Stoltenberg, who will chair the closed-door session of the North Atlantic Council, has said it was requested by Ankara in light of recent "heinous terrorist attacks."
The extraordinary meeting has been convened under Article 4 of the NATO founding treaty, which allows member states to seek such consultations when they consider their "territorial integrity, political independence or security" to be in jeopardy.
Ankara was expected to brief allies on measures it is taking but, according to sources with knowledge of the preparations for the meeting, it was not expected to request any air or troop support.
"NATO allies follow developments very closely and stand in solidarity with Turkey," Stoltenberg said while announcing the meeting of the council, which is the alliance's main decision-making body.
Rare, but more regular, meetings
The session is only the fifth so-called Article 4 meetings since the US-led alliance was formed in 1949. In the most recent instance, NATO ambassadors convened at Poland's request in March 2014, after Russia's annexation of Crimea from Ukraine.
The first three sessions were all called for by Turkey; once in 2003 over the invasion of Iraq, and twice in 2012 because of incidents on the Syrian border.
After months of being reluctant to take action against "Islamic State" (IS), Ankara last sent Turkish warplanes to attack IS targets in Syria. It came after a bombing of a town close to the Syrian border, Suruc, in which 32 people died, which Turkey attributes to IS.
Attacks on Kurdish positions pose risk
However, Turkey has also carried out strikes against the outlawed Kurdistan Workers Party (PKK), which has itself carried out terrorist attacks within Turkey. Those airstrikes have thrown into doubt the terms of a fragile ceasefire between the PKK and Turkey. It has also allowed the US to use its Incirlik airbase against IS.
Attacks on Kurds have also become a headache for the US, which works with troops from the Kurdish People's Protection Unit fighting IS on the ground.
Turkey and the US on Monday agreed on a plan to rout IS from a strip of Syrian land it still controls some 110 kilometers (70 miles) across, close to the Turkish border. The rest of the frontier is controlled by Kurdish fighters or Syrian rebels.
Turkish Prime Minister Ahmet Davutoglu said both Turkey and the US wanted to see Syria's moderate opposition forces replace IS near the Turkish border.
rc/jil (AP, AFP, dpa, Reuters)