Police in Kosovo and Italy say they have arrested an ethnic Albanian suspected of trying to recruit fighters to go to Syria and Iraq and promoting "terrorist" activities on social media.
Three of the suspects were arrested in Italy and one in Kosovo.
Police in Kosovo said officers had searched a man's house in a village in Hani i Elezit, 65 kilometers south of capital Pristina, where they found a pistol, a rifle and some electronic devices.
Police in Italy said the four suspects were very active on the Internet, promoting their pro-jihadist cause, but did not appear to have been involved in any specific plots.
"They were threatening the pope, celebrating the recent attacks in Paris and threatening the former U.S. ambassador to Kosovo," said Carmine Esposito, a police chief in the northern Italian city of Brescia, where the investigation was based.
A few hundred Kosovo-born volunteers have joined the Islamic State group in Syria and Iraq. They often appear on their propaganda videos warning of imminent attacks.
Based on reporting by AP and Reuters