The Archbishop of Canterbury is on a three-day visit to Ukrainian capital Kyiv in solidarity with the country's people and churches after months of war.
Speaking upon his arrival in the city, Archbishop Justin Welby condemned Russia's "illegal, unjust and brutal invasion" of the country.
During his three-day visit, he will meet Ukrainian church leaders to hear their experiences of the war and the additional challenges being presented by the onset of winter.
He will also meet with members of the Church of England church in the Ukrainian capital, Christ Church Kyiv.
"The people of Ukraine have shown extraordinary courage in the face of Russia's illegal, unjust and brutal invasion," the Archbishop said.
"This visit is about showing solidarity with them as they face a profoundly difficult winter.
"I look forward to meeting with church leaders and local Christians in Kyiv, and learning how we can continue to support them amidst the ongoing devastation, loss and destruction of this war."
En route to Ukraine, the Archbishop met Ukrainian refugees living in Warsaw, Poland, and heard from the Apostolic Nuncio to Poland, Archbishop Salvatore Pennacchio, about what the Roman Catholic Church is doing to support Ukrainian refugees there.
Archbishop Welby said that hearing the stories of the refugees in Warsaw was "deeply moving".
While in Ukraine, he will meet more refugees and internally displaced people, and hold discussions with local leaders about how the Church of England can support them and churches in Ukraine.
"In this season of Advent, we remember that Jesus was born into conflict and persecution - and became a refugee when his parents fled violence and persecution to seek safety in Egypt," he added.
"I urge Christians in the Church of England and around the world to keep praying for the people of Ukraine in this Advent season - along with all people caught up in conflicts around the world - and offering our solidarity and support in every way we can."
The Anglican Bishop in Europe, the Rt Rev Dr Robert Innes, who is accompanying the Archbishop on his visit, thanked Christians for the work they are doing to support Ukrainians affected by the war.
"I am very grateful to have this opportunity to travel to Ukraine to show my personal support for our brothers and sisters in Christ here at this difficult and painful time," he said.
"It is inspiring and humbling to see how members of our chaplaincy here at Christ Church in Kyiv continue to carry out their work and serve God in the face of the traumas of war.
"Archbishop Justin and I are here to show solidarity with all the churches in Ukraine as we continue to pray for a peaceful and just end to the war. I want to thank everyone here for making us so welcome.
"It was also inspiring to see the work of our chaplaincy in Warsaw and the Ukraine House which we visited on our way to Kyiv. I thank them too for the incredible work they – and others around our diocese – have been doing to support refugees who have fled Ukraine since the conflict began."
