NATO envoys held emergency talks at the request of Turkey, a NATO member, and scores of migrants began converging on Turkey’s border with Greece.

The airstrike came after a Russian delegation spent two days in Ankara for talks with Turkish officials on the situation in Idlib, where a Syrian government offensive has sent hundreds of thousands of civilians fleeing towards the Turkish border.

Defence Minister Hulusi Akar said that Turkey would not vacate any of its 12 observation posts in Idlib and warned that Turkish soldiers were under orders to retaliate forcefully to Syrian attacks on the military posts.

It was unclear what specific invitation Erdogan was referring to as the interior minister in the Tripoli-based government, Fathi Bashagha, suggested in comments to reporters in Tunis that no official request had yet been made.

Ambassador Kerim Uras was asked to respond to calls that Recep Tayyip Erdogan should be charged with war crimes.

Turkey's defence ministry said about 20 others were wounded when the bomb exploded in central Tal Abyad, which was captured last month by Turkey-backed opposition gunmen from Kurdish-led fighters.

The fighting underscored the risks of violence as multiple and often opposing armed forces jostle for new positions in the tight quarters of the northeastern border zone.

Syrian Kurdish-led forces and Turkey exchanged blame on Saturday for fighting that has rattled a U.S.-brokered cease-fire in northeastern Syria, as the Kurds appealed to Vice-President Mike Pence to enforce the deal.

The meeting came a day after a U.S. delegation led by Vice-President Mike Pence and Pompeo reached an agreement with Turkey to halt its week-old offensive against Kurdish forces in northern Syria.

The deal is designed to allow Kurdish forces to withdraw from a designated safe zone on the northern border.