VATICAN CITY -- Pope John Paul II has called for mass mobilization of Catholics to spread church teachings in a new wave of missionary activity, particularly to the Third World and even in countries where proselytizing is forbidden by Islamic law.

"The mission of Christ the Redeemer, which is entrusted to the church, is still very far from completion," the pope wrote at the outset of a 153-page encyclical released Tuesday. The mission must continue with the conviction that the Roman Catholic Church "alone possesses the fullness of the means of salvation," he said.

"As the second millennium after Christ's coming draws to an end, an overall view of the human race shows that this mission is still only beginning and that we must commit ourselves wholeheartedly to its service."

Titled "Redemptoris Missio", Latin for Mission of the Redeemer, the message is the eighth encyclical issued by the pope in his 12-year reign and the church's first major statement on missionary work in a quarter-century.

An encyclical is one of the most authoritative forms a papal pronouncement can take.

"From the beginning of my pontificate, I have chosen to travel to the ends of the earth in order to show this missionary concern," he wrote. "My direct contact with people who do not know Christ has convinced me even more of the urgency of missionary activity."

The encyclical states that missionary work has to be directed "to the South and the East," and that missionaries' greatest challenges would be in Asia, Africa and Latin America, where the numbers of non-Christians are growing.

"The number of those who do not know Christ and do not belong to the church is constantly on the increase," the pope said in the document addressed to Roman Catholics worldwide. "Indeed, {in the past 25 years} it has almost doubled. When we consider this immense portion of humanity which is loved by the Father and for whom He sent His Son, the urgency of the church's mission is obvious."

According to the Vatican, of the Earth's 5 billion people, "only one-third know and recognize Jesus Christ in terms of faith and only 18 percent are Catholics."

"Our own times offer the church new opportunities in this field; we have witnessed the collapse of oppressive ideologies and political systems; the opening of frontiers and the formation of a more united world due to an increase in communications; the affirmation among peoples of the gospel values which Jesus made incarnate in His own life {peace, justice, brotherhood, concern for the needy}; and a kind of soulless economic and technical development which only stimulates the search for the truth about God, about man and about the meaning of life itself," the pope wrote.

The aim of missionary work is "Christian conversion," including baptism, the encyclical noted. But the pope stressed that Catholics must be open to dialogue with non-Christians, a view he said is not incompatible with missionary work.

"Inter-religious dialogue is a part of the church's evangelizing mission," he wrote. "Understood as a method and means of mutual knowledge and enrichment, dialogue is not in opposition to the mission ad gentes {to the nations}; indeed, it has special links with that mission and is one of its expressions."

"In the light of the economy of salvation, the church sees no conflict between proclaiming Christ and engaging in inter-religious dialogue."

The pope said he had recently written the bishops of Asia, "Although the church gladly acknowledges whatever is true and holy in the religious traditions of Buddhism, Hinduism and Islam as a reflection of that truth which enlightens all men, this does not lessen her duty and reserve to proclaim without fail Jesus Christ who is 'the way, and the truth and the life' . . . dialogue should be conducted and implemented with the conviction that the church is the ordinary means of salvation and that she alone possesses the fullness of the means of salvation."

He called other religions "a positive challenge for the church."

"Redemptoris Missio is animated all through by a vigorous optimism," said Cardinal Jozef Tomko, prefect of the Congregation for the Evangelization of Peoples. "What's new in this encyclical comes really from this courage of faith and hope."

Commenting on the encyclical, Italian Archbishop Settimo Todisco, president of the Episcopal Commission for Missionary Cooperation Among Churches, said that the pope's own experience in traveling the world, particularly in countries with large non-Catholic populations, greatly influenced his message.

EXCERPTS FROM POPE'S ENCYCLICAL

Following are excerpts from the Vatican's official English-language translation of Pope John Paul II's encyclical, released Tuesday:

"From the beginning of my pontificate I have chosen to travel to the ends of the Earth in order to show this missionary concern. My direct contact with peoples who do not know Christ has convinced me even more of the urgency of missionary activity.

"The Second Vatican Council sought to renew the Church's life and activity in the light of the needs of the contemporary world . . . . The missionary thrust therefore belongs to the very nature of the Christian life, and is also the inspiration behind ecumenism . . . .

"The Council has already borne much fruit in the realm of missionary activity. There has been an increase of local Churches with their own bishops, clergy and workers in the apostolate.

"Nevertheless, in this 'new springtime' of Christianity there is an undeniable negative tendency, and the present document is meant to help overcome it. Missionary activity . . . appears to be waning. Difficulties both internal and external have weakened the Church's missionary thrust toward non-Christians, a fact that must arouse concern among all who believe in Christ. For in the Church's history, missionary drive has always been a sign of vitality, just as its lessening is a sign of a crisis of faith.

"Our own times offer the church new opportunities in this field: we have witnessed the collapse of oppressive ideologies and political systems . . . .

"No believer in Christ, no institution of the Church can avoid this supreme duty: to proclaim Christ to all peoples.

"The Second Vatican Council replies to those concerned with safeguarding freedom of conscience: the human person has a right to religious freedom . . . .

"The temptation today is to reduce Christianity to merely human wisdom, a pseudo-science of well-being. In our heavily secularized world a 'gradual secularization of salvation' has taken place, so that people strive for the good of man, but man who is truncated, reduced to his merely horizontal dimension.

"We know, however, that Jesus came to bring integral salvation, one which embraces the whole person and all mankind . . . .

"The Church is effectively and concretely at the service of the Kingdom. This is seen especially in her preaching, which is a call to conversion. Preaching constitutes the Church's first and fundamental way of serving the coming of the Kingdom in individuals and in human society . . . .

"The growth in the number of new Churches in recent times should not deceive us. Within the territories entrusted to these Churches -- particularly in Asia, but also in Africa, Latin America and Oceania -- there remain vast regions still to be evangelized . . . .

"Inter-religious dialogue is a part of the Church's evangelizing mission . . . . In the light of the economy of salvation, the Church sees no conflict between proclaiming Christ and engaging in inter-religious dialogue.

"If we look at today's world, we are struck by many negative factors that can lead to pessimism. But this feeling is unjustified: we have faith in God our Father and Lord, in his goodness and mercy . . . . Today in fact there is a new consensus among peoples about these values, the rejection of violence and war; respect for the human person and for human rights, the desire for freedom, justice and brotherhood; the surmounting of different forms of racism and nationalism; the affirmation of the dignity and role of women."