Pope Leo said on Sunday that he is following events after US-Israeli strikes against Iran with “deep concern” and made an impassioned appeal to stop what he called a “spiral of violence”.

“I address a heartfelt appeal to the parties involved to assume the moral responsibility to stop the spiral of violence before it becomes an irreparable abyss,” said the pope.

“Stability and peace are not built through mutual threats or through weapons … but only through reasonable, genuine, and responsible dialogue,” the pope said during his weekly address to pilgrims in St. Peter’s Square after a Sunday prayer.

Meanwhile in Moscow, Russian President Vladimir Putin said that the killing of Iranian Supreme Leader Ayatollah Ali Khamenei and members of his family was “cynical” murder that violated all the norms of human morality and international law.

“Please accept my deep condolences in connection with the murder of the Supreme Leader of the Islamic Republic of Iran, Seyed Ali Khamenei, and members of his family, committed in cynical violation of all norms of human morality and international law,” Putin said in a note to Iranian counterpart Masoud Pezeshkian released by the Kremlin.

Khamenei was killed on Saturday, aged 86, Iranian state media announced, in air strikes by Israel and the United States.

“In our country, Ayatollah Khamenei will be remembered as an outstanding statesman who made a huge personal contribution to the development of friendly Russian-Iranian relations and bringing them to the level of a comprehensive strategic partnership,” Putin said.

“I ask you to convey my most sincere sympathy and support to the family and friends of the Supreme Leader, the government and the entire people of Iran.”