Former UK Prime Minister Theresa May was concerned about the threat of ISIS

Britain and France considered sending up to 1,000 troops each to Syria after US President Donald Trump announced a sudden withdrawal of American troops from the wartorn country last December, a new report has revealed.

Mr Trump announced the planned US withdrawal in a tweet on December 19, 2018.

“After historic victories against ISIS, it’s time to bring our great young people home!” he tweeted, in a move in line with one of his campaign promises.

The deployment of troops, if enacted by the two European neighbours, would have replaced 2,000 US troops stationed in Syria.

An investigation by British newspaper The Telegraph that surfaced on Wednesday evening found that then British Prime Minister Theresa May thought that Mr Trump’s announcement would increase the threat of ISIS, as the terror group had not yet been defeated. It wasn’t until March this year that the last ISIS stronghold in Syria was taken by Kurdish forces assisted by the US.

The paper reported that Mrs May changed her mind about the plan after she doubted the US would provide air cover and the logistical support required for the deployment. The UK premier also feared that she would not be able to pass the motion through Parliament.

The report said many ministers weren’t briefed about the plans and only a small number of advisers and cabinet ministers were notified. Mrs May's defence secretary Gavin Williamson was apparently briefed and was supportive of the plan.

“It was properly thought about. It wasn’t just a one-off idea,” one UK source directly involved in the deployment discussions told The Telegraph.

Another UK defence source told the paper it was intended to be “a like-for-like” replacement.

The Pentagon, the Élysée Palace and the former British prime minister all declined to comment.

In October, Mr Trump began withdrawing US troops from northern Syria, allowing Turkish forces to launch an incursion into the country. The move was met with strong condemnation from Europe, as it saw the US abandon its Kurdish allies in the region, leading to thousands of people having to flee their homes.