Pope Francis on Saturday urged dialogue on both personal and political levels as he celebrated a second Christmas under the shadow of a coronavirus pandemic that was pushing people into isolation.

In his traditional Urbi and Orbi Christmas Day message to the faithful gathered in St Peter's Square at the Vatican, the pontiff also deplored that the "immense tragedies" in Syria, Yemen and Iraq were "being passed over in silence" and cautioned against fresh violence in the simmering conflict in Ukraine.

"In this time of pandemic...Our capacity for social relationships is sorely tried; there is a growing tendency to withdraw, to do it all by ourselves, to stop making an effort to encounter others and do things together," he said.

"On the international level too, there is the risk of avoiding dialogue, the risk that this complex crisis will lead to taking shortcuts rather than setting out on the longer paths of dialogue."

"Yet only those paths can lead to the resolution of conflicts and to lasting benefits for all."

Around the world, "we continue to witness a great number of conflicts, crises and disagreements. These never seem to end; by now we hardly even notice them. We have become so used to them that immense tragedies are now being passed over in silence," he said, mentioning Syria, Iraq and Yemen, among others.

"In Ukraine, prevent fresh outbreaks of a long-festering conflict," he said, as tensions mounted between Russia and the West over the fate of the strategic ex-Soviet country.