Nigel Farage has warned that ISIS fighters released from Syrian prisons could travel to the UK.
The Reform UK leader said the terror group has previously declared “they would send their operatives into Europe”.
Mr Farage said the security threat could be one of the reasons why the Home Office has paused decisions on asylum claims from Syrian nationals.
Home Secretary Yvette Cooper refused to rule out deporting asylum seekers back to Syria, as she admitted there is concern in the Home Office over a potential terrorist threat to the UK.
Mr Farage said: “Yesterday we saw Germany, Austria, Sweden, and then France, then slightly belatedly, the United Kingdom saying right, we’re halting all asylum applications.
“And I guess there are two reasons for that. One is, you could say, well, now that Assad has gone, it’s a perfectly safe country, so why should anybody want to claim asylum here?
“But the second and perhaps more sinister one is, does it mean that there’ll be people now leaving Syria? Maybe those who committed murderous acts in the name of Assad?
“Does it mean those who fought for ISIS that have maybe been freed from some of these prisons that might start to come in our direction?
“Maybe one very good example through which we can debate this is Shamima Begum. Should she now be allowed to return?
“Will she possibly be allowed to return? And remember, she’s lost every court case in this country.
“It’s complicated. No one quite knows how things will settle down in Syria.
“We can go all the way back to 2015 when the boats first started crossing the Mediterranean, when ISIS very, very boldly, publicly said they would send their operatives into Europe. And of course, that means, ultimately, in some cases, onto us.”
As of September, some 6,502 Syrians were awaiting a decision on their asylum claim in the UK. More than 27,000 Syrians have claimed asylum in the UK since the civil war broke out in 2011.
Ms Cooper defended the decision to suspend asylum applications from the war-torn nation.
She said: “Currently, what we’ve seen is people trying to cross the border from Turkey back into Syria, and so people traveling in that direction.
“That’s also why we have suspended asylum decisions in the UK for Syrian cases, because, of course, people were claiming asylum from the Assad regime, which is no longer there.
“So that’s why it’s right, like France and Germany, for us to suspend those asylum decisions, but we also need to closely monitor what is happening in Syria, because there’s so much instability.
“We don’t know yet what or how that will play out, or what that will mean.”
Austria is already preparing to deport migrants from Syria after the Assad regime fell.
Asked if the UK could follow suit, Ms Cooper said: “This was an issue we discussed at the Calais Group this morning.
“Germany, France, Belgium, the Netherlands and ourselves have all paused asylum decisions because people were claiming asylum from the Assad regime.
“That is no longer in place, so it would not be appropriate for us to take those asylum decisions forward, but we don’t yet know how things are going to play out.
“We will need new guidance for Syria for making those asylum decisions, but we also need to monitor what happens at the moment so that we can make for progress going forwards.”
Spy chiefs are on red alert over fears terrorists could escape from prisons in Syria and return to the UK, the Daily Express understands.
Intelligence analysts fear Syrian Democratic Forces will be dragged into fights with the Turkish-backed Syrian National Army and other rebel groups.
Thousands of former Isis fighters and other jihadists are being held in camps controlled by the Syrian Democratic Forces (SDF), a Kurdish-led group backed by the United States, in northeast Syria.
This is understood to include dozens of battle-hardened British jihadists.
Ms Cooper admitted: “Clearly everyone is pleased to see the end of the Assad regime and the huge damage that they have done.
“But of course, there is still concern about potential groups of extremists within Syria and what the implications will be there.
“So, we will need to monitor this extremely closely both from the point of view from our f policy but also from the point of view of security also.”
Asked to clarify that there is concern in the Home Office, Ms Cooper said: “The issue is about what the situation is in Syria.
“The situation in Syria has had implications across the globe and we will continue to monitor closely because we just don’t know how events are going to unfold.
“We’ve clearly seen the end of the Assad regime.
“That does mean potential opportunities for the Syrian people but also potential instability and of course there have been extremist groups operating in Syria over many years and so what we need to see is how this plays out.
“We’re going to be extremely vigilant throughout and are clearly monitoring what happens.”
