Pope says Vatican involved in secret Ukraine peace mission

"There is a mission in course now but it is not yet public. When it is public, I will reveal it," the pope told reporters during a flight home after a three-day visit to Hungary.

"I think that peace is always made by opening channels. You can never achieve peace through closure. ... This is not easy."

The pope added that he had spoken about the situation in Ukraine with Hungarian Prime Minister Viktor Orban and with Metropolitan (bishop) Hilarion, a representative of the Russian Orthodox Church in Budapest.

"In these meetings we did not just talk about Little Red Riding Hood. We spoke of all these things. Everyone is interested in the road to peace," he said.

Since Russia invaded Ukraine in February 2022, Francis has pleaded for peace practically on a weekly basis, and has repeatedly expressed a wish to act as a broker between Kyiv and Moscow. His offer has so far failed to produce any breakthrough.

Pope Francis, 86, has said previously that he wants to visit Kyiv but also Moscow on a peace mission.

Ukraine Prime Minister Denys Shmyhal met the pope at the Vatican on Thursday and said he had discussed a "peace formula" put forward by Ukrainian President Volodymyr Zelenskiy.

Shmyhal also asked for help in the repatriation of children. Kyiv estimates nearly 19,500 children have been taken to Russia or Russian-occupied Crimea since Moscow invaded in February last year, in what it condemns as illegal deportations.

"The Holy See is willing to do this (help repatriate the children) because it is the right thing," Francis said on the plane. "All human gestures help but gestures of cruelty don't help. We have to do all that is humanly possible".

Francis, who appeared in relatively good condition during the trip, also spoke of his health following his hospitalisation in late March for what the Vatican said at the time was bronchitis.

He said he felt a strong pain at the end of his general audience on Wednesday, March 29 and tried to sleep.

"I did not lose consciousness but I had a high fever and at 3pm the doctor took me to the hospital right away," he said.

"It was a strong and acute pneumonia in the lower section of the lung. Thank God I can talk about it. The body responded well to the treatment, thank God," he said. He was released on April 1.

A part of one of his lungs was removed when he was a young man in Argentina more than half a century ago.