The Archbishop of Westminster is encouraging people to fast and pray for Ukraine as Russian forces continue to bomb the country.
The invasion is into its eighth day; the UN predicts the death toll has already exceeded 2,000 people.
Cardinal Vincent Nichols, Archbishop of Westminster, said: "I have an overwhelming sense of dread. I can only imagine what people in the cities of Ukraine - Kyiv in particular - how they feel when they see that huge convoy of military assets being driven towards their city, and when they see city centres attacked by missiles.
"My heart goes out to them, and I just wish I could find some ways of strengthening their resolve."
Cardinal Nichols has issued his support for Ukrainian refugees to be welcomed to the UK.
He continued: "It's important that we act generously, but not recklessly. There needs to be a measure of appropriate care and preparedness for people to be welcomed here, but welcomed they should be."
Cardinal Nichols was urging people to dedicate the first day of Lent, Ash Wednesday, to fasting and prayer.
He continued: "As the people of Ukraine, you will see them pray before icons, and intercede for the prayers of Mary, the mother of Jesus, the Mother of God, before they engage. They know perfectly well the power of prayer, whether they're from an Orthodox tradition, or a Latin rite or Ukrainian Catholic tradition.
"You see the churches in this country here, filled this weekend, over and over again. People understand the power of prayer, they don't need me to explain it.
"Fasting is an absolute act of acknowledging my dependence on God.
"This is the beginning of Lent, and Lent is 40 days and just think, 40 days Moses with garden Sinai, 40 days of the temptation of Jesus in the desert, 40 days of preparation for Easter, as they had 40 years in the wilderness.
"These are deep, deep things, and we use lent on Ash Wednesday, is beginning to refresh and place ourselves again, before God."