Turkey to enter Syria war after US gives green light

The 150 or so US special forces that had been stationed there "will not support or be involved in the operation" and "will no longer be in the immediate area" when the Turks make their move, it added.

It also linked the decision to EU refusals to try and jail "foreign fighters" - European citizens who went to Syria to fight fo jihadist groups in recent years.

The US "has pressed France, Germany, and other European nations ... to take them back, but they did not want them and refused", the White House said.

"Turkey will now be responsible ... for all the [jihadist] fighters captured in the area," it added.

For his part, a Turkish spokesman said on Monday the new military operation would start without delay.

It would help create a "safe zone" in northern Syria and would "clean" that zone from "terrorist" groups, including from Kurdish groups which Turkey sees as posing a separatist threat to its own territory.

The US move is less drastic than Trump's decision to pull out of Syria altogether, which he abruptly announced last December after also talking to Erdogan by phone.

And Nato allies had tentatively agreed, in August, to create a safe zone for refugees near the Turkish border.

But the prospect of Turkish troops riding into battle in Kurdish-controlled areas raises the risk of enflaming the conflict still further.

Turkey's "threats are aimed to change the security mechanism into a mechanism of death, displace our people and change the stable and secure region into a zone of conflict and permanent war," the main Kurdish-led resistance army, the Syrian Democratic Forces (SDF), said on Sunday.

Any Turkish attacks would lead to "all-out war on the entire border to defend ourselves and our people", the SDF added.

Kurdish fighters have, in the past eight years, proved to be the West's most dependable allies in the wars against Syria's genocidal regime and against Islamist radicals.

For his part, Trump's former defence chief, James Mattis, resigned last December when Trump struck his first phone deal with Erdogan.

The Turkish defence minister said Kurdish militias would be "buried in their ditches" at the time.

France, Germany, and Denmark - America's main allies in a Western coalition on Syria - also complained about the US move.

"The protection of the populations of north-eastern Syria and the stability of this zone must be taken into account by the United States to avoid any new humanitarian drama," the French foreign ministry said then.

"Coordination between European countries is important to add pressure on the US to reconsider the decision," Denmark said.

But, Russian leader Vladimir Putin, who also has troops in Syria and who stands to gain influence there if the US pulls back, praised Trump's initiative.