Ukrainian President Volodymyr Zelensky has said he is thankful for the support and prayers of Pope Francis.
The Ukrainian Embassy to the Holy See said that Pope Francis had spoken with Zelensky by phone on Saturday.
During the call, the Pope expressed his "deepest sorrow for the tragic events" taking place in Ukraine.
The call followed an unprecedented surprise visit by the Pope to the Russian embassy in Rome to express his alarm over the invasion.
Vatican spokesman Matteo Bruni said Francis spent over half an hour at the embassy.
"He went to express his concern over the war," Bruni said.
On Twitter, President Zelensky thanked Pope Francis "for praying for peace in Ukraine and a ceasefire".
"The Ukrainian people feel the spiritual support of His Holiness," he said.
He expressed similar comments after speaking with Ecumenical Patriarch Bartholomew, who has called on Russia to end its invasion of Ukraine.
President Zelensky said on Twitter, "Thank you for the warm conversation, Your All-Holiness #Bartholomew. Your words are like hands that hold us up in this difficult time.
"Ukrainians feel the spiritual support and strength of your prayers. We hope for the soonest peace."