Four suspected “Islamic State” (IS) sympathizers were detained by Italian police during a “vast anti-terrorism operation” in northern Italy on Thursday, according to authorities.

Investigators intercepted an IS communication which ordered one of the suspects, a Moroccan-born man, to carry out attacks in Italy “with particular attention to the city of Rome,” Milan prosecutor Maurizio Romanelli told reporters.

The communication specifically focused on the Holy Year pilgrimage which is currently underway.

“This is a new profile, because it was not a generic indication, but an indication given to a specific person who was invited to act within the territory of the Italian state,” Romanelli said.