Libyan authorities have warned Italy of the presence of a Milan-based cell affiliated to the Islamic State (Isis) terror group. The revelation was made after Libyan authorities seized some documents when government troops took over an IS (Daesh) headquarter in the city of Sirte earlier in August.

It is believed the cell is associated with Abu Nassim, a 47-year-old Tunisian man who lived in Italy before becoming an IS commander in Libya, AFP reported.

The news came as Italian authorities ordered the expulsion of a Tunisian national accused of planning an attack at the Leaning Tower of Pisa. Bilel Chiahoui, 26, was arrested after he posted on social media messages threatening to attack the monument.

On 13 August, Interior Minister Angelino Alfano also ordered the expulsion of Tunisian imam Hosni Hachemi, accusing him of inciting racial hatred. Hachemi was also accused of recruiting fighters for terrorist cells, but he was later acquitted.

IS has repeatedly threatened to attack Italy. The latest of such threat was made earlier this month, when the group released a video claiming it would "conquer Rome".

The Islamist outfit also claimed that Sirte was the gateway to Rome in a graffiti found on the walls of Sirte by a militia group loyal to Fayez al-Sarraj's national unity government. The militias photographed, which have helped liberate most of Sirte, photographed the graffiti earlier in August.

Rome features heavily within IS's teachings. The terror group's distorted view of Islam claims that IS will eventually face and defeat an army from "Rome", which will lead to the rise of an 'anti-Messiah' figure who will in turn defeat IS and trigger Armageddon – the ultimate goal of IS's founders. However, it's unclear what "Rome" refers too: it could refer to Turkey (once the base of the Eastern Roman Empire) or any military force that opposes IS.

Libyan forces began their offensiveto recapture Sirte in May. The advance was slowed due to major causalities caused by IS landmines and snipers.

Libyan authorities warned Italy of the presence of a Milan-based cell affiliated to the Islamic State (Isis/Daesh) terror group