WASHINGTON - In his historic address to Congress, Pope Francis urged lawmakers to embrace immigrants, abolish the death penalty, and protect families while also calling for the U. S. to help avert climate change.

Tens of thousands of spectators watched from the West Lawn of the Capitol as the pope addressed a House chamber packed with Supreme Court justices, Cabinet officials, lawmakers and others.

The pope opened his historic speech by describing himself as a "son of this great continent" joined in a common purpose with America. The Argentine-born pope is the first from the Americas, and his speech to Congress is the first by any pontiff.

He called for a "delicate balance" in fighting religious extremism to ensure that fundamental freedoms aren't trampled at the same time. He said in his speech that "no religion is immune from forms of individual delusion or ideological extremism." He says religious, intellectual and individual freedoms must be safeguarded, while combatting violence perpetrated in the name of religion.

Francis has expressed deep concern about the slaughter of Christians and other religious minorities in the Middle East at the hands of Islamic extremists, fearing that the Christian presence in the region is risk. He's dispatched envoys to Iraq with money and other forms of assistance to help refugees.

He also urged Congress and the U. S. as a whole to be more welcoming of immigrants and treat them as fellow human beings. The son of Italian immigrants to Argentina himself, Francis noted that the United States was founded by immigrants, that many lawmakers are descended from foreigners, and that this generation must not "turn their back on our neighbors."

His plea: "Let us treat others with the same passion and compassion with which we want to be treated."

The pontiff's admonition comes as the presidential race is roiled by questions about immigration from Mexico and Latin America, and the nation is weighing how many migrants to accept from wars in the Middle East.

In his remarks about ending the death penalty, a very unpopular idea among U. S. lawmakers, the pope also referenced the church's opposition to abortion. He said lawmakers and all Americans should "protect and defend human life at every stage of its development," though he did not specifically call for an end to abortion in the U. S.

The pope also lamented that the very basis of marriage and family life today is being put into question - an allusion to gay marriage in a country that recently legalized same-sex marriage across the land. He said the family today is "threatened, perhaps as never before, from within and without."

While Francis has shown great openness to gays as individuals, he has staunchly upheld the church teaching that marriage is a union between man and woman. Sitting in front of Francis for his speech was John Roberts, chief justice of the Supreme Court, which legalized gay marriage across the country. Francis is expected to speak in greater depth about the threats to families at a big church rally in Philadelphia later this week.

Francis also directly addressed climate change, something conservative U. S. lawmakers have taken issue with. In his address Francis urged a "courageous and responsible effort" to avert the most serious effects of what he called the "environmental deterioration caused by human activity."

Francis says he's convinced that working together, nations can make a difference to slow global warming. He says the U.S. and "this Congress" have an important role to play. Now, he says, is the time for a "culture of care."