In the wake of the terror attack that left more than 80 people dead in Nice last night, Archbishop of Canterbury Justin Welby has issued an urgent call to prayer.
"As the French rejoice in their liberty, human evil kills the innocent cruelly," he wrote on his Facebook page.
"Let us weep with them, let us stand with them. #PrayForNice."
The Vatican also released a statement condemning the attack, which occurred as the French celebrated Bastille Day on Thursday.
"We have followed during the night, with the greatest concern, the terrible news which has come from Nice," said papal spokeman Fr Federico Lombardi.
"We want to make known, on the part of Pope Francis and ourselves, our sharing and solidarity in the suffering of the victims and all the French people, in what was supposed to be a great day of celebration.
"We condemn in an absolute manner every manifestation of homicidal folly, hatred, terrorism, and attacks against peace."
Bishop Robert Innes, the Church of England's Bishop in Europe, assured the people of Nice and France of his prayers.
"The terrible events of last night, which was to have been a day of national celebration, have reminded us that we must yet again stand together as men and women in the face of violence. I continue to pray for peace and, today in particular, we hold in our prayers the victims of this attack and their families," he said.
"We also pray for Fr Peter Jackson and the people of Holy Trinity, Nice, situated so close to the Promenade des Anglais who, along with all faith communities of the city, will minister to all affected by this tragedy. May you be strengthened by the prayers of the whole Diocese, your brothers and sisters in Christ."
The Church of England on Twitter offered a prayer for Nice:
The official death toll climbed through the night, but the current figure is at least 84 people killed, including many children.
A gunman drove a 19-tonne lorry into a crowd that had gathered to watch fireworks in Nice, also injuring hundreds, 18 of them critically.
French president Francois Hollande said in a national address "We cannot deny that it was a terror attack" and extended the country's state of emergency by three months. "France has been hit on the day of celebration. This is a form of sabotage. Human rights are not respected by these fanatics," he said.
The UN Security Council branded the attack "barbaric and cowardly", while US President Barack Obama called it "horrific", and said in a statement: "We stand in solidarity and partnership with France, our oldest ally, as they respond to and recover from this attack."
New British foreign secretary Boris Johnson said on Twitter: "Shocked and saddened by the appalling events in Nice, and the terrible loss of life."
According to the Telegraph, the lorry-driver was a 30-year-old French-Tunisian "well known to the police for armed attacks".
He was shot dead by police officers after exchanging fire.
