Pope Francis met with friends and families of victims of the Nice terror attacks on Saturday as he looked to comfort them and urged them resist the temptation to "respond to hatred with hatred and to violence with violence".

"I desire to share your pain", he told them as he promised to pray for their loved ones who had died. He said the Church "remains close to you and accompanies you with immense compassion". 

He also used his address in the Vatican to tell those who were "attacked by the demon" to respond with "forgiveness, love and respect for your neighbour" rather than giving in to the temptation to react with hate and violence. Earlier this week he denounced any form of violence within religion and insisted "there is no God of war". 

Among the some 1,000 people who attended the ceremony were members of Nice's Jewish community and a local Muslim imam.

"It makes me happy to see that inter-religious relations are very vibrant among you, and this cannot but soothe the wounds left by this dramatic event," said Francis.

Islamic State (IS) militants claimed responsibility for the July 14 Nice attack. Less than two weeks later, IS militants killed an elderly French priest, Father Jacques Hamel, in his church, prompting the pope to declare the "the world is at war".

But the pope also insisted the war was not a religious one, and that it was wrong to "identify Islam with violence", suggesting instead that the lack of economic opportunities for young people in Europe was one of the causes of terrorism.

After speaking briefly, the pope descended from the pulpit and spent more than 45 minutes meeting those who attended the ceremony, many of whom were in tears.

Additional reporting from Reuters.