NEW YORK -- Pope Benedict XVI yesterday upheld the United Nations as a crucial defender of human rights and a force for peace, while warning that unless those human rights are considered God-given, they will be subject to erosion or revocation.

In one of the most anticipated stops on his U.S. tour, Pope Benedict told the U.N. General Assembly that the rights encoded in the U.N's 1948 Universal Declaration of Human Rights "apply to everyone by virtue of the common origin of the person, who remains the high-point of God's creative design for the world and for history."

"They are based on the natural law inscribed on human hearts and present in different cultures and civilizations," he said.

His six-day visit was in response to an invitation to speak to the assembly, as Popes John Paul II and Paul VI had done before him. He built on their themes of peace and human rights.

Speaking in French and English -- and offering a greeting of "peace and prosperity with God's help" in six languages including Arabic and Chinese -- the pope denounced go-it-alone superpower strategies to solve global problems.

"Indeed, questions of security, development goals, reduction of local and global inequalities protection of the environment, of resources and the climate, require all international leaders to act jointly and to show a readiness to work in good faith, respecting the law and promoting solidarity with the weakest regions of the planet. I am thinking especially of those countries in Africa and other parts of the world which remain on he margins of authentic integral development."

But he endorsed international intervention when one nation can't or won't protect its own people from either natural or man-made crises.

Although the pope did not mention Iraq or any other nation by name, prior to the U.S.-led military invasion -- and speaking as Cardinal Joseph Ratzinger before he became pope -- he said Catholic teaching did not have a place for the idea of a "pre-emptive war" to prevent a feared worse one. Since the invasion, he has repeatedly deplored the continuing violence in Iraq but has not called for an immediate U.S. withdrawal.

His advocacy of coordinated, outside intervention in desperate situations was a key point of his address, said Stephen Colecci, director of the Office for International Justice and Peace of the U.S. Conference of Bishops.

"If you look at papal talks, clearly he has called for international action to protect the people in Darfur. He has called for international cooperation to resolve the Israeli-Palestinian conflict," he said. "He's very concerned about the Middle East in general, particularly the condition of minorities, but all of the people," Dr. Colecci said. "He's also thinking of the responsibility of the international community toward very poor nations where basic food and shelter are lacking."

A section of the talk on the sacred "order of creation" could reflect concern about topics from abortion, to gay marriage, to protection of the environment, but the pope likely had new bioethical issues such as cloning uppermost in his thoughts, Dr. Colecci said.

Although there are great benefits from scientific research, "some instances of this represent a clear violation of the order of creation, to the point where not only is the sacred character of life contradicted, but the human person and the family are robbed of their natural identity," Pope Benedict said.

"Likewise, international action to preserve the environment and to protect various forms of life on earth must not only guarantee a rational use of technology and science, but must also rediscover the authentic image of creation. This never requires a choice to be made between science and ethics. Rather, it is a question of adopting a scientific method that is truly respectful of ethical imperatives."

Pope Benedict has a green streak and under his administration key Vatican buildings are being converted to solar power. But the church opposes abortion and artificial contraception -- the latter especially when it is coerced -- to limit the human population.

Human rights, the pope said, are the key to world peace and security.

"Indeed, the victims of hardship and despair, whose human dignity is violated with impunity, become easy prey to the call to violence," he said.

He held up religious freedom as a primary human right, because if people are not free to act peacefully on their deepest beliefs about the meaning of life, they are not free at all.

"It is inconceivable, then, that believers should have to suppress a part of themselves -- their faith -- in order to be active citizens," he said. "It should never be necessary to enjoy one's rights."

He indicated that he was speaking not only of oppressively atheistic states, but those where members of one faith have more rights than others, and that religious liberty was not only the right to worship but for religious minorities to participate fully in public life without hiding their beliefs.

Far from encouraging violence, he said, religious faith contributes to peace because "recognition of the transcendent value of every man and woman favors conversion of heart, which then leads to a commitment to resist violence, terrorism and war, and to promote peace and justice."

Archabbot Douglas Nowicki of St. Vincent Archabbey in Latrobe was at the U.N. for the address and said everyone appeared moved by the pope's words.

"He really came as a representative of all humanity to make an appeal for people of every faith and no faith to address issues of common concern, such as justice, and to care for those people throughout the world who are economically marginalized," he said. "It was a very strong appeal to work for peace."

As it was in Washington, the pope was surrounded by well-wishers all day.

Several hundred supporters, many of them Hispanic, turned up outside the U.N., standing behind metal police barricades as Pope Benedict spoke.

A group of New Jersey Catholics held up a banner for the German-born pope that combined German -- "Willkommen Pope Benedict XVI" -- and English sentiments: "You Rock!"

A small anti-pope contingent included a group calling itself Forum for Protection of Religious Pluralism. Financial consultant Padmanabh Rao, a Hindu from Woodbridge, N.J., complained that the Vatican is converting people in India to Catholicism.

Before the pontiff's speech, Pope Benedict and Secretary-General Ban Ki-moon met alone for 15 minutes for what the Vatican called a discussion on a range of international issues.

Later, speaking to U.N. staff members, Pope Benedict paid tribute to 42 civilians and peacekeepers killed in 2007. He said the United Nations plays a key role in monitoring how well governments protect their citizens.