Pope Francis tasted two extremes of Washington on Thursday, going from the pomp of a speech to Congress to the gut-punch of a meal for the homeless.

In both venues, he was a hit.

US lawmakers and other VIPs gave the pontiff repeated standing ovations as he appealed for more action in the global migrant crisis, the fight against climate change and other woes.

It was the first speech ever by a pope to a joint meeting of the American legislature.

From Capitol Hill, he headed straight to a luncheon with the homeless, where he was treated to a friendly mobbing, with the lucky invitees scrambling around him for a handshake or a cell phone picture. He smiled broadly.

The 78-year-old Argentine pope's close-up look at the flip sides of life in Washington came on the second and last full day of his visit to the US capital, before he heads to New York and then Philadelphia over the weekend.

The visit to the Catholic Charities dining facility for the homeless at St. Patrick's Church was particularly poignant. Some 200 homeless men, women and children were invited to lunch, and asked to wear their Sunday best, which they did.

For the occasion, a white tent-like structure was set up to accommodate everybody, and the tables had white tablecloths. One man sat reading a Bible.

Pope Francis blessed the food -- teriyaki chicken, pasta salad, green beans and carrots -- and told the guests "buen apetito" in Spanish, or enjoy your meal. But he did not stay to break bread with them.

- 'Out of this shelter' -

"I hope he keeps on blessing me and helps me find a place to get out of this shelter," James Murphy, 68, who has lived in one for two years, said as he awaited the pope, CBS News reported.

The pope is known to be fond of close-up contact with the poor as part of his emphasis on focusing the church on day-to-day social problems.

The day started on a much more solemn note as Francis pressed some of his trademark battles in the speech to Congress.

Three crisp raps of the gavel from the podium announced the arrival of the pope, who wore flowing white vestments as he strode down to the front of the chamber to applause and a standing ovation.

Francis spoke heavily accented English in a wide-ranging speech that touched on social, financial and humanitarian issues.

He addressed one of the most tragic crises of the day -- the relentless flow into Europe of Africans, Afghans and people from the Middle East, mainly Syrians fleeing their country's ruinous war.

"Our world is facing a refugee crisis of a magnitude not seen since the Second World War," he said.

But he also spoke of the plight of poor Central Americans and Mexicans who make dangerous, often deadly treks across the Mexican border into the United States.

In both cases, he said, all people want is a chance for a better life.

"We must not be taken aback by their numbers, but rather view them as persons, seeing their faces and listening to their stories, trying to respond as best we can to their situation," he said.

To some extent, the Pope was speaking to deaf ears in Congress.

Despite pushes from Obama, the Republican-controlled Congress has failed to approve a sweeping reform that would have helped the estimated 11 million people, mostly Latinos, living in the United States without residency papers to gain legal status.

Many Republicans say the first priority should be securing the US border.

- 'Make a difference'-

On climate change, the pope alluded to a recent encyclical in which he denounced global warming as a woe caused by mankind.

"I am convinced that we can make a difference, I'm sure, and I have no doubt that the United States -- and this Congress -- have an important role to play. Now is the time for courageous actions and strategies," the pope said.

A major global climate conference is scheduled for December in Paris. The goal -- elusive in several previous gatherings as rich polluters like the US and developing ones like Brazil and China failed to reach agreement -- is to strike a deal to cut greenhouse gas emissions blamed for global warming.

On other issues, the pope called for a worldwide end to the death penalty -- the US is one of the few countries that still practice it -- and denounced the global arms trade as being fueled by hunger for "money that is drenched in blood."

After his speech, the pope stepped out onto a balcony overlooking the National Mall and greeted tens of thousands of cheering well-wishers down below.

He switched to Spanish -- "buenos dias," he said, eliciting a roar of approval -- and asked God to bless the crowd.