REUTERS (ASSISI) - As Pope Francis visits the central Italian town of Assisi calling for world forgiveness, security around him is noticeably tight.

A three-ringed perimeter is in place around the basilica, and thousands of people are checked two or three times as they approach.

The visit comes a day after Italian police announced heightened security around the Vatican and other religious sites in Rome.

It is not clear whether this comes in response to a specific threat, or the recent murder of a Catholic priest in a French church.

"To offer today's world the witness of mercy is a task from which none of us can feel exempted. The world needs forgiveness; too many people are caught up in resentment and harbour hatred, because they are incapable of forgiving. They ruin their own lives and the lives of those around them rather than finding the joy of serenity and peace," said the Pope.

Assisi is the birthplace of St. Francis, whom the pope is named after. St. Francis is most associated with peace and protection of the environment.