"We expect concrete support from all our allies to this struggle," he said alongside the NATO's chief during a visit to Brussels, adding that it was Turkey making a major sacrifice in Syria.

"NATO is in a critical process in which it needs to clearly show its alliance solidarity" with Turkey, Erdogan added.

Erdogan also called on NATO to fulfill previous commitments it has made to bolster Turkey's defences.

His visit to Brussels comes as pressure mounts on European countries after Erdogan said he would no longer hold back refugees heading to the West.

Turkey is home to 3.6 million Syrian refugees.

Nearly a million people in Syria's northwestern province of Idlib have fled towards the Turkish border triggered by an offensive by the Syrian regime backed by Russian air power.

Turkey lost more than 50 troops to regime fire in Idlib in February alone.

"Our allies should display their solidarity with our country without discrimination and without laying down political conditions," Erdogan said.

"It is very important that the support we demand is met without any further delay."

He also blasted Greece for blaming Turkey for the recent migrant crisis.

"It is irrational and inconsiderate that an ally and a neighbouring country put the finger of blame on Turkey for the irregulation migration," he said.

"We will not allow this country to try to get unfair gains by abusing the current situation and the European Union."