Rome - Four terrorist suspects accused of supporting the Islamic State militant group and targeting Pope Francis were arrested on Tuesday in a joint operation by Italian and Kosovar police, Italian authorities said.The Islamist Kosovars hailed last month's attacks in Paris on the internet and threatened further violence, the officials said.The leader of the group was arrested in Kosovo while the remaining three suspects were detained in Italy.Prosecutor Tommaso Buonanno said in the northern city of Brescia, that the most alarming threats were directed at the pontiff, adding that one posted online said, "There won't be any pope after this one. This is the last."The suspected leader of the cell had lived earlier in Italy and is accused of being a follower of ISIS, which claimed responsibility for the Paris attacks, which killed 130 people. He was found with weapons in his possession, authorities said.The other three suspects are to be deported to Kosovo.Interior Minister Angelino Alfano said the groups was uncovered thanks to intensive monitoring of the internet and its Italian base was in Brescia province. They are also accused of threatening former US ambassador Tracy Ann Jacobson on Facebook and saying France would be the target of further attacks, Alfano said.Italian authorities are concerned that ISIS will carry out attacks in Rome during the Jubilee of Mercy, a holy year declared by the pope that begins December 8. Millions of pilgrims are expected to visit Rome and the Vatican during the celebrations.