ROME, Italy — The head of the Vatican’s office for promoting Christian unity has accused Russian Patriarch Kirill of “heresy” for his defense of his nation’s war on Ukraine.

Vatican Cardinal Kurt Koch said, “It is heresy that the patriarch dares to legitimize the brutal and absurd war in Ukraine for pseudo-religious reasons,” in an interview published Wednesday in the German newspaper Die Tagespost.

“To play down Putin’s brutal war of aggression as a ‘special operation’ is a misuse of language. I have to condemn this as an absolutely impossible position,” the cardinal stated.

Koch also declared that from a Christian point of view, “one cannot justify a war of aggression, but at most, under certain conditions, defense against an unjust attacker.”

Second Vespers presided over by Cardinal Kurt Koch  during the 54th Week of Prayer for Christian Unity in the Basilica of St. Paul Outside the Walls. (Grzegorz Galazka/Archivio Grzegorz Galazka/Mondadori Portfolio via Getty Images)

As Breitbart News reported, on Sunday Patriarch Kirill asserted that Russia is proceeding on the right path in its aggression against Ukraine and deserves “very strong cohesion and consolidation.”

“God willing, our spiritual strength shouldn’t wane, so that we shouldn’t have any fears and any feeling of uncertainty about our historical development,” in clear reference to the Ukraine war.

“Everything that’s happening now is happening the right way, although our way is not easy,” he added.

In early May, Pope Francis had a Zoom meeting with Patriarch Kirill, after which he sharply criticized the patriarch as playing the part of Putin’s “altar boy.”

“I spoke to Kirill for 40 minutes via zoom,” Francis said in an interview with the Italian daily Corriere della Sera. “He spent the first twenty reading me all the justifications for the war from a notecard in his hand.”

“I listened and told him: I don’t understand anything about this. Brother, we are not state clerics, we cannot use the language of politics, but that of Jesus,” the pope recounted. “We are shepherds of the same holy people of God. For this we must seek ways of peace, to put an end to the firing of weapons.”

“The Patriarch cannot transform himself into Putin’s altar boy,” Francis continued, the equivalent of calling him Putin’s lapdog.