Vatican City - Pope Francis hailed the unifying power of sport on Sunday ahead of the Olympic and Paralympic Games, and repeated his call for a worldwide truce during the event.

"Sport has a great social strength, capable of peacefully uniting people of different cultures," he told pilgrims in St. Peter's Square after his weekly Angelus prayer, ahead of the Olympics opening ceremony on Friday in Paris.

"I hope that this event can be a sign of the inclusive world that we want to build and that the athletes, with their sporting testimony, be messengers of peace and effective models for young people in particular," the 87-year-old said.

"According to the ancient tradition, the Olympics are an occasion to establish a truce in wars, demonstrating a sincere desire for peace."

Pope Francis has repeatedly called for a ceasefire in Israel's brutal assault on Gaza, respect for international law in the war between Russia and Ukraine, and peace in other conflict regions around the world.

The Olympic Games in Paris, France, run from July 26 to August 11, followed by the Paralympic Games from August 28 to September 8.