GETTY • IG ISIS supporters have said the terror group has sleeper cells all across Europe

FREE now SUBSCRIBE Invalid email Make the most of your money by signing up to our newsletter fornow We will use your email address only for sending you newsletters. Please see our Privacy Notice for details of your data protection rights.

And most frighteningly of all - terror experts have backed up the chilling claims. During the migrant crisis it was feared jihadists could sneak through the European Union’s porous borders as thousands arrived into the continent daily from war-torn nations. This included in July, Mohammad Daleel, a 27-year-old failed asylum seeker, who blew himself up outside a party in Ansbach, Germany. ISIS later said he was a "soldier of the Caliphate".

There was doubt around the claims as the man was said to have mental health issues and had previously attempted suicide. But now Express.co.uk has seen online material from ISIS supporters, claiming sleeper cells are waiting to attack. One ISIS supporter boasted over Telegram app about upcoming attacks which he claimed would be as deadly as those in Nice and Paris. He said: ”There are many cells being set up. "That Islam will bring fear upon their land and each home. "And many more attacks are carded. "And on the way in many forms and fashions.

PH Jihadists have carried out repeated attacks on the west this summer

TELEGRAM The jihadist included a number of threats to Europe

TELEGRAM The ISIS fanatic used app Telegram for the gloating

Islam will bring fear upon their land and each home Jihadist

"Until they stop." The jihadist, who claims to be 28, said Muslims who support the caliphate attack Europe because of the war in Syria. He also claimed those killed in Nice and Paris should have stopped their national governments from getting involved in the war in Syria. He said: "Victory is by Allah and with the Muslims. "What is to happen is to happen with no consequences to anyone "What makes the citizens normal or innocent? "When this is their rule or else stand up and abolish the governments." Political scientist Colin Clarke from the American think-tank RAND has warned Europe not to take the claims lightly.

GETTY The jihadists says terrorists have infiltrated the migrant streams

The fight against ISIS Fri, November 18, 2016 The battle against ISIS militants (also abbreviated as Daesh, ISIL, IS and Islamic State) continues in the Middle East. Play slideshow Getty 1 of 183 Forces battle against ISIS

The expert warned how complacency cannot be afforded in Europe, since ISIS is known for waiting and planning attacks. He said: “This is a very patient group, so if there are jihadists that have already infiltrated various European countries, they could be in the process of gathering the logistics and materials necessary to conduct an attack, which could happen at any time. “The attack on the Brussels airport was initially supposed to be targeting the European Championships, from a few sources I've read, and was only moved up and the target changed after the arrest of Salah Abdeslam. "They've proven adept at inspiring lone wolves and individuals across the globe to strike out in their name. I wouldn't discount the possibility that the group has operatives pre-positioned to strike in Europe in the future." Last year, Europol said they feared jihadists were training in Europe, but were unable to release any more information. It has long been claimed dozens of ISIS fanatics have crossed into the continent.

GETTY Nice attacks shocked the world in July

Mr Clarke believes there may be many more than authorities are currently unaware of. He said: "I think we've seen this to be true and beyond what we already know, I would suspect that the odds are that there were probably more. "Why wouldn't ISIS use this as a way to sneak operatives into Europe? "Moreover, there are hundreds of fighters from various European countries that have connections to low level criminals and militants in their countries of origin, people who never left. This is one of the more dire situations in my opinion.”