Pope Francis has revealed that he received an angry phone call from German Chancellor Angela Merkel after he compared Europe to a "barren woman", in an interview published Monday.

In a speech to the European Parliament in November 2014, Pope Francis delivered a withering attack on a "haggard" Europe which he said is "now a 'grandmother', no longer fertile and vibrant."

In an interview with Italy's Corriere della Sera, Francis said he had received an angry phone call from Merkel afterwards.

"She was a bit angry because I had compared Europe to a barren woman, incapable of producing children," Francis said.

"She asked me if I really thought Europe could no longer make children.

"I told her yes it can, and many, because Europe has strong and deep roots," he said, adding that "in the darkest moments, it has always shown itself to have unexpected resources."

In the wide-ranging interview, the Argentine pope also said he believes Russia can make a significant contribution to world peace.

And he expanded on why he is so keen on the bridge building that led to the announcement of a historic meeting with the Patriarch of the Russian Orthodox church, which will take place on Friday in Cuba.

"You have to build bridges, step by step," he told his interviewer. "Up to the point where you can shake the hand of the person on the other side."

Like China, "Russia has a lot to give," he added, even emphasising that the Vatican and Moscow's views had converged at times over recent crises in the Middle East.

Friday's meeting will be the first between the heads of the Roman Catholic and Russian Orthodox churches since an 11th Century schism between the Eastern and Western branches of Christianity.