Donald Trump is being warned that the withdrawal of US troops from Syria will put Christians and other minorities at risk of an ISIS resurgence.

The US president's unexpected move shook allies and was quickly followed by the resignations of General James Mattis as Defense Secretary and Brett McGurk, the president's special envoy to the Global Coalition to Defeat ISIS. 

UK defence minister Tobias Ellwood has cautioned against a US pull-out, saying the threat from ISIS is still 'very much alive'.

Now Christians in the region are begging the US not to withdraw troops.  The Syriac Military Council has issued a statement appealing to the Global Coalition to protect religious and ethnic minorities. 

'Turkey's mercenary troops, who fought with al-Qaeda and ISIS, are waiting to get the green light to move into Syria, so that they can kill all 'infidels' of the region.  That means Christians, Yazidis, Kurds, and other minorities,' it said. 

They pleaded with the US 'not to leave abruptly' before security is ensured, warning that churches will be destroyed while Christians and Yazidis are 'killed and massacred'. 

Sanharib Barsoum, President of the Syriac Union Party, said in an open letter to the US that 'ISIS is far from dead'. 

'If Turkey is allowed to destroy us, America will be standing by as the only glimmer of hope in the Middle East is crushed,' he said. 

'All the gains of US effort will be lost and two thousand years of history of Christianity in north-east Syria will be erased forever.'

It added: 'If the US pulls out now and Turkey invades, ISIS will return.'

Amy Austin Holmes, an associate professor at the American University in Cairo and a visiting scholar at Harvard University's Weatherhead Scholars Program, shares their fears. 

Writing in The Hill, she said that if Trump moved ahead with the withdrawal of troops, it could prompt Turkey to launch another assault and lead to a potential 'free-for-all' in north-east Syria. 

'Trump's unilateral decision to withdraw US troops from Syria will embolden our adversaries, including Iran, Russia and Syrian leader Bashar al Assad, and weaken and betray our Kurdish and Arab partners in the Syrian Democratic Forces (SDF),' she said.

'A withdrawal would also endanger the civilian population living inside the safe haven that is now under SDF control — approximately 35 percent of the country and home to some 6 million people.

'The inhabitants of this area are ethnically and religiously diverse, including Kurds, Arabs, Muslims and a Christian minority estimated to include some 100,000 people.'