The measures were adopted after a foreign intelligence agency, possibly American, intercepted a conversation between two unidentified Arabs in which they reportedly discussed 'doing something in the Vatican'.
The Vatican downplayed the threat, with Federico Lombardi, its main spokesman, saying that it had not received indications of a 'particular threat or cause for concern.' Iraq's ambassador to the Holy See warned this week that Isil saw the Pope as a legitimate target and might try to assassinate him, because of his outspoken concern for the plight of Christians in Iraq and Syria and his conditional support of US bombing raids against Isil forces.
The news came a day before Francis's trip to Albania, where the pontiff is expected to mingle with the crowds as usual despite reports of possible danger from new Islamic State recruits returning from the Middle East to the mostly-Muslim country.
Some worry the pope has made himself a target by speaking out against the Islamic State group and having the Holy See voice support for US air strikes in Iraq.
In an interview with Italy's La Nazione daily this week, Iraq's ambassador to the Holy See, Habib Al Sadr, said "what has been declared by the self-declared Islamic State is clear. They want to kill the pope. The threats against the pope are credible."