VATICAN CITY (CNS) -- In a letter to his nuncio in Russia, Pope Francis called out those who would claim Russia's war on Ukraine had any spiritual justification.

Saying he wanted to speak on behalf of the war's victims, Pope Francis said that "their cry rises to God, invoking peace instead of war, dialogue instead of the din of weapons, solidarity instead of partisan interests, because one cannot kill in the name of God."

Russian leader Vladimir Putin and Russian Orthodox Patriarch Kirill of Moscow have both claimed God is on Russia's side as they promoted the war as, in part, a fight against the "evil" West.

Pope Francis and Patriarch Kirill had had a 40-minute Zoom conversation a month after the war began in 2022. The pope later told a reporter, "I listened to him" read a list of reasons justifying the war, "and I told him, 'I don't know anything about this. Brother, we are not clerics of the state, we cannot use the language of politics, but of Jesus. We are shepherds of the same holy people of God. That is why we must seek the path of peace, to cease the blast of weapons.'"

"The patriarch cannot turn himself into Putin's altar boy," Pope Francis said in the May 2022 interview with the Italian newspaper, Corriere della Sera.

The pope had written in November to his nuncio in Ukraine, sending assurances of his sorrow and his prayers on the 1,000th day since Russia began its large-scale invasion in February 2022.

His letter to Archbishop Giovanni d'Aniello, the nuncio in Russia, was dated Dec. 12 and printed on the front page of the Vatican newspaper Dec. 14.

As people prepare for Christmas, "the day on which the son of God, prince of peace, appeared on the earth," Pope Francis said he wanted to share with his nuncio in Russia "my prayer and my heartfelt appeal that peace would reign among people and would be reborn in the hearts of all men and women, who are loved by the Lord."

The continued fighting, the pope said, "urgently challenges us, reminding us of the duty to reflect together on how to alleviate the suffering of those affected and rebuild peace."

Pope Francis also said that he hoped people's prayers and the humanitarian efforts to alleviate people's suffering would "pave the way for renewed diplomatic efforts, which are necessary to halt the progression of the conflict and to achieve the long-awaited peace."