Protesters converged on the Mall on Tuesday afternoon to call on Congress to pass a comprehensive overhaul of the nation’s immigration and border control laws by year’s end.

At least 100 people were arrested, including several members of Congress, after demonstrators sat down in the street in front of the Capitol. Protesters had vowed to engage in civil disobedience, and their fellow marchers cheered as each person was led away in handcuffs by Capitol Police.

Among those arrested were several lawmakers, including Reps. Luis V. Gutierrez (D-Ill.), Charles B. Rangel (D-N.Y.), John Lewis (D-Ga.) and Jan Schakowsky (D-Ill.). Gustavo Torres, head of Casa de Maryland, immigration lawyers, priests and labor activists also were taken into custody. The protesters were charged with “crowding, obstructing and incommoding,” a spokesman for the Capitol Police said.

An immigration bill is stuck in the House, and its prospects have dwindled as lawmakers are preoccupied with the government shutdown and budget talks. The rally’s organizers hoped to ramp up pressure to bring the measure to a vote.

Organizers predicted that tens of thousands of people would attend the “Camino Americano: March for Immigrant Dignity and Respect” rally, featuring performances by popular Latino musicians and speeches by members of Congress as well as civil rights, religious and community leaders. But the crowd was considerably smaller, and grew even smaller after a popular singing group finished its performance.

Many who came waved handheld American flags, an image that also adorned placards identifying unions beside slogans such as “The time is now” and “Justice and dignity.” The deep thrum of a drum punctuated the speeches, and many in the crowd chanted, “Si, se puede!” — or “Yes, we can!”

“I believe immigrant rights are human rights,” said civil rights icon Julian Bond, among the first to speak. “Immigration reform must come. It will come.”

House Minority Leader Nancy Pelosi (D-Calif.) emphasized that “the full diversity” of Democrats in the House supports the immigration measure she introduced last week, and she presented leaders of the African American, Asian and Latino caucuses.

“The blood of immigrants flows through all our veins,” she said.

Proclaiming an overhaul of immigration policy good for the economy, she predicted it would help reduce the deficit in decades to come.

Immigration advocates have declared October a month of escalating pressure for a comprehensive immigration bill. They say they fear that momentum has stalled since June when the Senate approved a sweeping, bipartisan plan that features a 13-year path to citizenship for most of the nation’s 11 million undocumented immigrants.

The Republican-controlled House has not voted on that bill, and GOP leaders have said they are pursuing a series of smaller-scale bills focused primarily on increased border security and workplace visas.

Proponents of the bill are concerned that the government shutdown and bitter fight between Congress and the White House over the budget and debt ceiling will leave little time for lawmakers to focus on immigration, though some Republicans have vowed to take up the issue later this month.

“It’s going to be extremely tough to get comprehensive immigration reform, but it’s not impossible,” said Terry O’Sullivan, general president of the Laborers’ International Union of North America, which counts many immigrant workers among its members, mostly in construction and in lead and asbestos abatement.

Many in the crowd listened intently to Los Tigres Del Norte, a norteño band from San Jose, Calif., that has built a wide following with emotional ballads about life, love and survival. Some of the band’s most popular songs are about illegal immigration.

Mario Lopez, 53, sang along to a ballad about divided loyalties to the Mexican and American flags. Lopez drove to the rally from Ocean City, where he and his wife both work in beach restaurants.

“I left my first family behind, I came and worked for 13 years, and my three older children are all studying with money I sent back,” Lopez said. “I love Mexico, but it is so dangerous now, there is so much killing and the pay is so low.”

His wife, Idena, 48, who like Lopez has no legal documents, cried as she recounted how she could not return to Mexico to see her parents before they died.

“I just want to tell the government to stop dividing families who work hard and give up so much,” she said.

The Rev. Carmelo Santos, a lecturer at Georgetown University who is pastor of a church in Springfield, said he witnessed the impact of immigration reform after President Obama signed an executive order barring deportation of residents brought to the United States as children.

“It was almost like [they were] saying, ‘I exist now, I am a person,’ ” said Santos, who said most of his congregation came to the United States from El Salvador, Honduras and Bolivia.

Some rally-goers said they are optimistic that the growing number and political clout of immigrants may revive chances for legislative proposals that have stalled.

“My hope comes from unity,” said Diana Salazar, 49, an activist from Charleston, S.C., who arrived on a train with six other people to attend the rally. “The census numbers woke up a lot of people in many states and small towns. There are too many of us now. They can’t just put us on a bus and send us all back.”

One of the rally’s goals was to highlight the record number of deportations by the Obama administration, which have been estimated at more than 1,000 per day. Obama has called immigration reform his top domestic priority in his second term, but he disappointed activists last month when he said he would not use executive authority to expand a deportation deferment program for young people, who are known as “Dreamers.”

Religious leaders played a prominent role in Tuesday’s rally. Several dozen who attended have worked for years on revising immigration legislation.

“I think there is a sense of urgency. If we don’t pass something now, we won’t get a vote until after the next election,” said the Rev. Gay Jennings, president of the House of Deputies of the Episcopal Church and the mother of an adopted son from Colombia.

Dozens of clergy members and faith advocates went to the Capitol, where they said they planned to give lawmakers Bibles and Torahs with sections about the migrant underlined.

The Rev. Peter Morales, president of the Unitarian Universalist Association, told the conference about meeting families who were separated at the border. “Our laws are more than broken, they’re evil.”

Michelle Boorstein, David Nakamura and Leah Binkovitz contributed to this report.