A re-emergence of Isis is “inevitable” after Donald Trump effectively greenlit Turkey’s invasion of northern Syria, the French prime minister has said.

"This is devastating for our security with the inevitable resurgence of Islamic State in northeastern Syria and probably also northwest Iraq and so the destabilisation of a government that doesn't need that," Edouard Phillippe told deputies in the French national assembly.

He accused Washington of allowing and strengthening the Turkish offensive because of its decision to unilaterally withdraw 1,000 troops from Syria.

Hundreds of relatives of Isis members have escaped from Kurdish-held camps in recent days, as guards have been diverted to the front line.

France has been among the most proactive EU member states in opposing the Turkish military operation, cutting off arms to its Nato ally and putting sanctions on the table.