Italy kosovo Isis
Italian and Kosovar authorities arrested four alleged Islamist militantsItalian Police

Italian authorities have busted an alleged Islamist terror cell that threatened both the Pope and a US diplomat, as well as spreading jihadi propaganda. The operation, carried out with Kosovar authorities, led to the arrest of four people – all Kosovo nationals.

Three were held in Italy, while the fourth – alleged ringleader Imishiti Samet – was detained in the village of Hani i Helezit, south of Pristina. They are facing accusations of defending terrorism and inciting racial hatred in a series of online postings.

Incriminating remarks included a Facebook comment by Samet in which the former bricklayer, who used to live in Italy, said that former US ambassador to Kosovo Tracy Ann Jacobson "deserved to be punished under sharia law".

Kosovar authorities told Italian media the Samet is affiliated to Islamic State (Isis) and has taken part in unspecified armed conflicts abroad. Detectives searching his address found a gun and a rifle, prompting the Italian police chief leading the investigation to say there was a risk the would-be jihadists could have turned threats into action.

In another social media comment, the four attacked Christian institutions, claiming Pope Francis was set to become "the last pope ever". They also praised the Paris attacks and shared photos of them holding weapons "in circumstances characteristic of Islamic State fighters", according to police in the northern Italian city of Brescia.

The police operation was nicknamed "Van Damme" after action movie actor Jean-Claude, who was cited by one of the four men in an online comment to images of Islamist violence. "We are not Rambo or Van Damme but we get things done for real," the message read, according to La Repubblica newspaper.

Italian authorities said they are to expel two of the arrested while the third is to remain in custody.