Supporters of the terror group claim their operatives have arrived in Europe. AFP / Getty Images

A series of alarming images have been posted on social media by Isis supporters, warning that the terror group are heading into Europe.

With Rome's iconic Coliseum as the backdrop, the chilling images published on Twitter count down 'till the zero hour'.

The photos have been taken at landmarks and train stations across Italy. A piece of paper displays the Islamic state logo with messages such as "Islamic State in Rome. We are in your streets."

One post was accompanied by the Arabic for "#Islamic State in Rome. Now is observing and locating for the target. Waiting for the zero hour."

The pictures hone in on prominent venues in Milan, including the city's cathedral and the Expo exhibition. Some of the pictures feature police vehicles in the background, demonstrating the terror group's brazen confidence.

The jihadist group have previously identified Rome, the home of Christianity, as a symbolic target. Demonstrating their intent, the front page of their propaganda magazine earlier featured a mock-up of the black flag of ISIS flying over St Peter's square.

The images were translated and published by the terror watch website Site, however their authenticity cannot be independently confirmed.

Libyan intelligence claims that IS are using the Mediterranean refugee emergency to send its operatives into Europe as tens of thousands of migrants surge across the shore.

Minister of Information Omar al Gawari of the Tobruk elected government told Italian news agency ANSA: "In the next few weeks Italy will see the arrival of boats carrying not only poor immigrants from Africa but Daesh (IS)."

Abdul Basit Haroun an advisor to the Libyan government said the militant group was using the trade in trafficking to smuggle their own men into Europe.

He told BBC Radio 5 live: "They give permission for the boat owner to use the spot under their control and they charge them for that 50/50 of whatever they make. They use the boats for their people who they want to send to Europe as the European police don't know who is from IS and who is a normal refugee or not.

"The boat owners have a list of who to take but some people come suddenly out of the list and they're told take them with you. They sit down separately they come alone and in the boat they are not scared at all. They are for IS 100 per cent."