Saleh, a Kurd himself, called in a tweet for the world "to unite to avoid a catastrophe".

Turkish forces launched its broad assault in northeastern Syria earlier Wednesday, made possible by the withdrawal of US troops.

The Kurdish forces, backed by the United States, had spearheaded five years of ground battles against the Islamic State (IS) group in Syria.

Iraq, which chased IS jihadists out of its country in 2017, regularly comes under attack from IS cells operating in mountainous country along the border with Syria.

Several countries fear that a resumption of fighting in northeastern Syria could herald a revival of the Islamic, as thousands of captured IS fighters are being held in camps run by the Kurdish People's Protection Units (YPG) militia.