Republican Donald Trump vows to send home all Syrian refugees if he is elected, saying they could be ISIL members.

Republican presidential front-runner Donald Trump has said he would send back Syrian refugees taken in by the US if he is elected president.

Trump said during a rally in New Hampshire on Wednesday that he was worried the refugees could be disguised members of the Islamic State of Iraq and the Levant (ISIL) group.

“I am putting the people on notice that are coming here from Syria as part of this mass migration, that if I win, if I win, they are going back, they are going back. I am telling you, they are going back,” Trump said.

His remarks came the same day Russian warplanes began air raids in Syria’s centre and north – their first military engagement outside the former Soviet Union since the occupation of Afghanistan in 1979.

“Look, if Russia wants to go in there, [it] would have been nice if we went in as a unified front, to be honest. But if Russia wants to go in there and knock out ISIS [ISIL] and maybe stabilise, this big migration with 200,000 people into the United States …” Trump later reiterated to CNN.

“If I win, I’m going to say it right now, and I’ll say it to you, those 200,000 people – they have to know this and the world will hear it – are going back.

“We’re not going to accept 200,000 people that may be ISIS [ISIL]. We have no idea who they are. And I’m telling you now, they may come in through the weakness of [President Barack] Obama,” but would return to their homeland if Trump makes it to the White House, he said.

US to accept tens of thousands more refugees

Millions of Syrians have been fleeing a civil war that has killed more than 250,000 people since March 2011.

But Trump questioned why Syrians were fleeing their country instead of staying and fighting.

Secretary of State John Kerry announced earlier this month that the US would significantly increase the number of refugees it takes in over the next two years.

So far this year, it has taken in about 1,500 Syrian refugees.

Kerry said the US will increase the number of refugees it takes in by 15,000 over each of the next two years, bringing the total to 100,000 in 2017.

The US will accept 85,000 refugees from around the world next year, up from 70,000, he said. Many of them will be Syrians.