NATO demanded on Wednesday evening an immediate end of "aggressive acts" against Turkey after a mortar bomb fired from Syria killed five Turks.

Following an emergency meeting, NATO ambassadors said in a statement that Syria's recent "aggressive acts" are "a flagrant breach of international law and a clear and present danger to the security" of Turkey.

They strongly condemned the recent mortar shelling, which "constitutes a cause of greatest concern" for all NATO countries.

"The alliance continues to stand by Turkey and demands the immediate cessation of such aggressive acts against an ally, and urges the Syrian regime to put an end to flagrant violations of international law," the statement concluded.

NATO ambassadors once met in June this year, at Turkey's request, after the downing of a Turkish jet by Syrian forces. The allies said they "remain seized of developments" on the Turkish-Syrian border.

At least five people were killed and 13 others wounded by artillery shells which fell in Turkey's southeastern Sanliurfa province from Syria on Wednesday.

In response to the mortar shelling, Turkey attacked targets in Syria, a statement released by Turkish prime ministry said.