Cardinal Pietro Parolin, the Vatican Secretary of State, was speaking to a meeting of world leaders about the migrant crisis at the UN earlier in the week.
He said: "Many reports confirm that Christians are by far the most persecuted faith group."
Vatican Radio has reported that the Holy See also called on the UN not to "abandon them".
The cardinal stressed the Pope's calls to stop the manufacturing of weapons, saying that "the availability and use of low technology weaponry has resulted in the spread of conflict, especially in countries and societies where the rule of law is fragile and poverty is widespread."
He also said that the UN had a duty to investigate the poverty, hunger and persecution suffered by believers all over the world.
