VATICAN CITY -- Warning that the world was drifting toward the "logic of war," Pope John Paul II called for a day of prayer and fasting for peace on Ash Wednesday.

The pope announced the move Feb. 23 as he appealed once again against war in Iraq. He said armed conflict in the Persian Gulf state could throw the entire Middle East into turmoil and raise tensions across the globe.

A peaceful future for the world cannot be won by terrorism or by war, the pontiff said from his apartment window above St. Peter's Square.

"For months the international community has lived in great anxiety over the danger of a war that could upset the entire region of the Middle East and aggravate tensions which unfortunately are already present at the start of the third millennium," he said.

"Believers, whatever their religion, should proclaim that we will never be able to be happy opposing each other, and that the future of humanity can never be assured by terrorism and the logic of war," he said.

He said Christians in particular are called to be "sentinels of peace" in the places where they live and work and to help make sure people do not give in to selfish interests, lies and violence.

Therefore, the pope said, he was asking Catholics in every country to fast and pray for peace -- especially in the Middle East -- on Ash Wednesday, March 5, the start of the Lenten season.

"We will above all implore from God the conversion of hearts and the wisdom of just decisions to resolve with peaceful and adequate means the disagreements that hinder humanity's pilgrimage in our time," he said.

He said particular attention should be given that day to praying the rosary -- in families, parishes and Marian sanctuaries around the world.

The pope said fasting on Ash Wednesday this year should be an "expression of penitence for the hatred and violence that pollute human relations."

He pointed out that Christians share the ancient practice of fasting with men and women of other faiths.

"With them, Christians want to strip themselves of all pride and prepare themselves to receive from God the greatest and most necessary gifts, in particular the gift of peace," he said.

In praying for Mary to guide the prayer and fasting initiative, the pope quoted from the beatitudes, "Blessed are the peacemakers, for they will be called children of God." He said that invocation needs to resound with new force in today's world and find practical application.