John Paul also used the occasion of his visit to the largely Muslim Egypt--about 10 percent of its 60 million people are Christian--to deplore the Muslim-Christian violence in Nigeria that claimed upwards of 200 lives in rioting this week.
``I pray to God that the people in that country will try to live in peace,'' he said.
In calling for renewed talks, John Paul noted some of the first efforts at Orthodox-Catholic reconciliation came with the Copts and he urged both Catholic-Coptic and Catholic-Orthodox talks resume.
``Please God,'' John Paul said, ``this International Joint Commission (between the Roman Catholic and the Coptic Orthodox Church) and the Joint International Commission for Theological Dialogue between the Roman Catholic and the Orthodox Church will soon function normally once more, especially in view of certain fundamental ecclesiological questions needing clarification.''
Orthodox-Catholic relations, always strained, were broken off last year at the time of the NATO bombing of largely Orthodox Serbia.
John Paul made his plea for the resumption of talks during an afternoon prayer service with Shenouda and other non-Catholic Christian leaders on the second day of a three-day visit to Egypt. The visit was the first leg of a spiritual pilgrimage to biblical sites associated with what the pope calls ``the history of salvation.''
The ``common witness'' of Catholics and Orthodox, he said, ``is all the more important at the beginning of a new century and a new millennium, which present enormous challenges to the human family. For this reason too, there is no time to lose.
``As a basic condition for this common witness, we must avoid anything which might lead once again to distrust and discord,'' John Paul said.
Pope Paul VI and the Patriarch Shenouda took important first steps when they agreed at their historic first meeting in the Vatican in 1973 to ``avoid any form of proselytism'' and to respect each other's ``ecclesial traditions and sacramental practices,'' John Paul said.
But, he said, ``We do not know each other sufficiently: Let us therefore find ways to meet! Let us seek viable forms of spiritual communion, such as joint prayer and fasting or mutual exchanges and hospitality between monasteries.
``Let us find forms of practical cooperation, especially in response to the spiritual thirst of so many people today, for the relief of their distress, in the education of the young, in securing humane conditions of life, in promoting mutual respect, justice and peace, and in advancing religious freedom as a fundamental human right.''
Georgette Achou was typical of the many who came to see the pope.
She said rose shortly after midnight Friday morning, dressed in the winter chill and drove to Alexandria's Sacred Heart Catholic Church to catch a ride to Cairo.
After waiting a lifetime to meet Pope John Paul II, a three-hour bus drive from the port city to the stadium was a comparative cakewalk for the 69-year-old Egyptian nurse. ``It's a benediction,'' Achou said, standing amid a sea of cheering spectators as John Paul, resplendent in gold and cream robes, celebrated the morning Mass. ``I couldn't see him in Rome. So I see him here.''
By foot, car, bus and metro, Egyptians streamed into the enclosed stadium, to hear the 79-year-old pontiff celebrate the Mass. There were Catholic nuns from Cairo, Coptic Christian farmers from rural Egypt, a sprinkling of Muslims and scores of families from all Christian denominations.
``It's his first time here and I don't know if I'll ever be able to see him again or not,'' said Neda Kerba, 26, who is a Copt. ``Changes will happen with his visit. Muslims and Christians will be together more than before.''
The same message of unity was sounded by the Polish-born pontiff during the Mass. He delivered his homily in French on a stage strewn with yellow and white flowers.
``Your presence around the successor of Peter is a sign of unity of the Church or which Christ is the head,'' the Pope told his mostly Christian audience.
``May the fraternity among all the Lord's followers, so clearly manifested here, encourage you to continue your efforts to build communities united in love.''
The pope sat for much of the service, and his hands trembled visibly. But he spoke in a strong voice as he praised the work of the different churches in Egypt, including their efforts to pass on the Christian faith to the country's young.
Banners were draped around the cavernous stadium offering greetings to the pope in English, French and Italian.
``L'Egitto Tiama Bienvenito Tranoi''--Egypt loves you, welcome among us--read one. Even a small, red ``Polska'' sign peeked out from one corner of the packed stadium to welcome the Polish pontiff.
As the pope appeared, walking slowly behind a procession of church dignitaries, the crowd erupted into cheers and clapping. Spectators began chanting ``John Paul II, we love you.'' Some women even ululeyed, sending out the high-pitched cry customary during Egyptian celebrations.