Black smoke rises ominously in Syria after military strikes by Turkey at the start of an offensive experts fear could lead to a wave of terrorism in nations such as Britain.
War planes, tanks and artillery began pummelling towns and cities in a fierce cross-border assault on Kurdish forces.
As ground troops rolled into North- East Syria last night, there was a warning the invasion could cause the nation to fall into anarchy again, allowing thousands of battle-hardened terrorists to rise up to form Islamic State II.
One expert said Britain may face an even “greater threat than before”.
Turkey is attacking Kurdish forces who are allied to the West and who guard prisons teeming with IS fighters.
Turkey’s pathway was opened by Donald Trump ’s decision to pull out US forces from northern Syria.
Sources in Britain’s Ministry of Defence say Trump’s “treacherous” move has caused shockwaves in Whitehall.
An insider told the Mirror: “This is being seen as an irresponsible and foolish move which will alienate those people in the Middle East who have been our allies in fighting IS.
“It is deeply dishonourable and stupid.”
Syrian Democratic Forces have branded Trump’s decision a “stab in the back”.
US House of Representatives Speaker Nancy Pelosi said it “betrays our Kurdish allies”.
The Kurdish-controlled Syrian town of Tell Abiad came under heavy Turkish shelling as palls of smoke rose over the city of Ras al-Ain. The Turkish border town of Nusaybin was hit by six Kurdish rockets fired from Qamishli, in Syria, a town that has until yesterday been virtually untouched by the war.
Kurdish-led forces said last night they had “repelled” a ground attack by Turkish troops.
Turkey’s President Recep Tayyip Erdogan wants to create a “buffer zone” in Syria between Turkey and the Kurds, who his country dubs terrorists.
Last night it emerged 14,000 Syrian rebel fighters had signed up to back Turkey against the Kurds, with commanders ordering them to show no mercy.
It is feared SDF troops could be overrun or pulled away from the prisons full of IS fighters.
Colonel Richard Kemp, who commanded British forces in Afghanistan and advised the government on counter terrorism, said: “There’s no doubt Islamic State is very much still a threat to the West and, of course, Britain.
“We face a grave threat from Islamic State and it is possible a US withdrawal and Turkey entering Syria could create conditions for a revival of IS.
“And if that happens, if terrorists are allowed freely to plot attacks locally and also against the West we could see a greater threat to Britain than before.”
British special forces are in northern Syria in small numbers in operations against remaining pockets of IS.
Former British Army officer and Syria expert Colonel Hamish de Bretton Gordon said US withdrawal could mean “we have a few weeks to act, otherwise Islamic State could become just as potent a terrorist force as it was before”.
Foreign Secretary Dominic Raab said: “I have serious concerns about the unilateral military action Turkey has taken.
“This risks destabilising the region, exacerbating humanitarian suffering and undermining the progress made against Daesh [IS].”
Britain and other allies were yesterday planning to raise their concerns to the UN Security Council.
Labour leader Jeremy Corbyn said: “I am deeply concerned at the actions of the Turkish military in the Kurdish areas of northern Syria and the security of the Kurdish people.
“There needs to be a withdrawal of all foreign forces from Syria.”
Q. Why is Turkey attacking Kurds in North-East Syria?
A. Because it views Syrian Kurdish fighters as terrorists who support other Kurds who have launched attacks in Turkey. They also prefer their old enemy Syria to be unstable, and peace has broken out lately.
Q. Why should Britain care?
A. Because the Kurd-dominated Syrian Democratic Forces were trained by British and US troops to defeat Islamic State and they lost 11,000 comrades in brutal fighting. Crucially, because IS could attack the UK again if the Kurds are beaten by Turkey, since it is their SDF force that stood between us and the terrorists.
Q. Is the violence contained?
A. It’s a very dangerous time because Turkish troops have been backed by Syrian rebels, some of whom served in extremist groups.
Anarchy in North-East Syria could let IS surge back into action, sparking attacks in Europe.
While Iran and Russia supported Syria’s Assad regime, Turkey was quietly helping IS by turning a blind eye to illegal border crossings.
Q. What can be done to stop it?
A. Donald Trump has threatened to hit the Turkish economy if President Recep Erdogan’s troops go too far, which they no doubt will.
The West must lean on Turkey to show restraint and stop turning what is already a kind of proxy war into something far worse.
Q. How significant is Turkey’s attack in a war that has seen unsurpassed levels of horror?
A. It is hugely significant and the timing is terrible. An uneasy peace had broken out in Kurdish-controlled North-East Syria and the IS terrorists had been almost contained.
Sleeper cells are at large but have remained quiet. Turkey’s action could be the signal for a new awakening of terrorism in the region, stretching across into Europe.
The Syria-Turkish border, now more in tatters than ever before, has been a main conduit for terror in Syria thanks to Turkey turning that blind eye. Just to complicate things further, Turkey is a member of NATO.
Trump has threatened to “totally destroy” Turkey’s economy if the push into Syria goes too far.
British troops are also taking part in secret missions to try to guard extremist camps in North-East Syria, home to tens of thousands of refugees such as exiled British jihadi bride Shamima Begum.
British jihadist prisoners such as ‘Jihadi’ Jack Letts are also in SDF prisons.
There are also fears that IS has thousands of fighters holed up in sleeper cells in Syria, ready to rise up if war breaks out there again.
The SDF are a Kurdish-led force aimed only at fighting IS.
They have lost 11,000 men and women fighting IS over five years. Some were trained by ex-Paras from Britain.
Roughly half a million people have died since the conflict began in Syria in 2011.
It is unknown how many Kurdish civilians have been killed in those eight years.
Erdogan has threatened to resettle two million refugees in North Syria.