President Recep Tayyip Erdogan said on Friday that Turkey had "no doubt" that Syrian Kurdish fighters were behind the attack on a convoy of military buses in Ankara that left 28 dead.

"We have no doubt that the perpetrators are the YPG and PYD," Erdogan said in Istanbul, referring to the main Syrian Kurdish militia and their political wing. He added he would speak to US President Barack Obama by phone later Friday to warn him over "the weapons support they (the United States) give to those organisations."