A jihadi Telegram -- an encrypted messaging service popular with militants -- praised the economic chaos that came in the wake of the EU Referendum and urged followers to strike at the heart of mainland Europe, the Mirror reported citing SITE intelligence group.
The UK voted to leave the European Union after 43 years in the historic referendum. Leave won by 52 per cent to 48 per cent votes.
UK military chiefs have warned there is a "serious and direct threat to holiday resorts across Europe" from groups like ISIS.
"There is considered to be a heightened threat of terrorist attack globally against UK interests and British nationals from groups or individuals motivated by the conflict in Iraq and Syria," the UK's Foreign Office (FCO) was quoted as saying.