While aboard the papal plane on the way to his Malta visit, the pope said Saturday that he was considering a trip to the Ukrainian capital Kyiv.

Asked by a reporter on the plane taking him from Rome to Malta if he was considering an invitation made by Ukrainian political and religious authorities, Pope Francis answered, "Yes, it is on the table." He gave no further details.

Francis has been invited by Ukrainian President Volodymyr Zelenskyy, Kyiv Mayor Vitaliy Klitschko, Major Archbishop Sviatoslav Shevchuk of Ukraine's Byzantine-rite Catholic Church and Ukraine's Ambassador to the Vatican, Andriy Yurash.

He has spoken on the phone with Zelenskyy and Shevchuk.

Since the invasion, which Russia calls a "special military operation" to demilitarise Ukraine, the pope has strongly condemned what he has called an "unjustified aggression" and denounced "atrocities."

But he has only referred to Russia directly in prayers, such as during a special global event for peace on March 25.