Pope Francis said in an interview published on Tuesday that he asked for a meeting in Moscow with Russian President Vladimir Putin to try to stop the war in Ukraine but had not received a reply, Reuter reports. 

The pope also told Italy's Corriere Della Sera newspaper that Patriarch Kirill of the Russian Orthodox Church, who has given the war his full-throated backing, "cannot become Putin's altar boy".

Francis, who made an unprecedented visit to the Russian embassy when the war started, told the newspaper that about three weeks into the conflict, he asked the Vatican's top diplomat to send a message to Putin.

The message was "that I was willing to go to Moscow. Certainly, it was necessary for the Kremlin leader to allow an opening. We have not yet received a response and we are still insisting".

Before the interview, Francis, 85, had not specifically mentioned Russia or Putin publicly since the start of the conflict on Feb. 24. But he has left little doubt which side he has criticised, using terms such as unjustified aggression and invasion and lamenting atrocities against civilians.

Asked about a trip to the Ukrainian capital Kyiv, which Francis last month said was a possibility, the pope said he would not go for now.

"First, I have to go to Moscow, first I have to meet Putin ... I do what I can. If Putin would only open a door," he said.