Recalling the victims of the "inhumane terrorist attacks," John Paul said: "We seek consolation and comfort for their families and relatives, prostrate from grief."

He also invoked "strength and courage" for those still working at the attack sites and "tenacity and perseverance for all men of good will to continue down the paths of justice and peace."

John Paul spoke at the start of monthlong gathering of bishops from around the world.

"From the heart of man, may the Lord uproot every trace of rancor, hostility and hatred, and render it open to reconciliation, solidarity and peace," the pontiff said.

In a reference to Christians, Muslims and Jews, a prayer read aloud in Arabic asked God to "grant wisdom of heart to all those who recognize Abraham as the father of faith."

The pope ended the ceremony with this prayer:

"Look down on our sorrowful human condition tested by ferocious acts of terror and death, comfort your sons and open our hearts to hope, so that our time may still know days of serenity and peace."

Among those speaking at the ceremony was an Anglican churchman, the Rev. Peter Foster of Chester, in Britain.

He wondered aloud if the U.S.-led military strikes in Afghanistan "will indeed put an end to terrorism or will it just encourage more of it?"

The Vatican has indicated that any "just war" must be conducted in proportion to the goal and not harm innocent civilians.