Francis, elected a week ago as the first non-European pope in 1,300 years, met leaders of non-Catholic Christian religions such as Orthodox, Anglicans, Lutherans and Methodists, and others including Jews, Muslims, Buddhists and Hindus.
"The Catholic Church is aware of the importance of furthering respect of friendship between men and women of different religious traditions," the Argentine pontiff told the religious leaders in an audience at the Vatican.
Speaking in Italian in the frescoed Sala Clementina, he said members of all religions and even non-believers had to recognise their joint responsibility "to our world, to all of creation, which we have to love and protect.
"We must do much for the good of the poorest, the weak, and those who are suffering, to favour justice, promote reconciliation and build peace," he said.
Francis told the religious leaders to fight "a one-dimensional vision of a human person, according to which man is reduced to what he produces and what he consumes," which he said was "one of the most dangerous snares of our times".
While he said history had shown that any attempt to eliminate God had produced "much violence," he reached out to those who seek truth, goodness and beauty without belonging to any religion.
"They are our precious allies in the commitment to defend human dignity, build a more peaceful coexistence among people and protect nature with care," he said.
Francis' description of people who belong to no religion as "precious allies" in the search for truth was a marked contrast to the attitude of former Pope Benedict, who sometimes left non-Catholics feeling that he saw them as second-class believers.
Since his election a week ago, Francis has set the tone for a new, humbler papacy, calling on the Church to defend the weak and protect the environment.
In another sign of his simpler style, Francis addressed the religious leaders while seated in a beige armchair and not the usual elaborate throne used in the ornate hall for audiences.
"I feel a great deal of excitement and optimism and hope," said Jerusalem-based Rabbi David Rosen, International Director of Inter-religious Affairs for the American Jewish Committee.
"He is deeply committed to the Catholic-Jewish relationship," Rosen, who attended the meeting, told Reuters.
Yahya Pallavicini, a leader of Italy's Muslim community, said he was impressed by the pope's insistence of inter-religious friendship.
"Friendship is a core way to increase brotherhood between believers and also to increase the deepness of the dignity of humanity," he said after the meeting.
"We can't consider man only as a consumer or as someone who has to be considered only in terms of the market but as a believer and as a person who has the holiness in his heart."
Before his address, the pope had a private meeting with Ecumenical Patriarch Bartholomew from Istanbul, who attended Francis's inaugural Mass on Tuesday.
It was the first time the spiritual head of Orthodox Christians had attended a Roman pope's inaugural Mass since the Great Schism between western and eastern Christianity in 1054.
At Wednesday's meeting, Francis called Bartholomew "my brother Andrew," a reference to the apostle who was the brother of St Peter and was the first bishop of the Church of Byzantium.
Francis also held a private session with Metropolitan Hilarion, the foreign minister of the Russian Orthodox Church, the largest in the Orthodox world.
Also at Wednesday's meeting was Abe Foxman, national director of the Anti-Defamation League in the United States.
Foxman is a Jew born in Poland in 1940 and saved from the Holocaust by his Polish Catholic nanny, who raised him as a Catholic during the war and then returned him to his family. His parents survived the war but 14 family members were killed.
"I asked him to bless the memory of the Catholic nanny who saved my life and he said he would," Foxman told Reuters.
Archbishop of York John Sentamu led a delegation from the Anglican Communion.
Other guests included World Council of Churches General Secretary Rev Olav Fykse Tveit and Jordan's Prince Ghazi bin Muhammad, head of an Islamic group that launched a dialogue with the Vatican after Pope Benedict angered Muslims in 2006 with a speech that implied their faith was violent and irrational. — Reuters