Despite low temperatures and steady rain, hundreds of people turned out Saturday to the Mall for “We Shall Not Be Moved,” a march led by the Rev. Al Sharpton. The rally called for togetherness in weathering the Trump administration and protecting civil rights. (Marvin Joseph/The Washington Post)

In a steady light rain, thousands of demonstrators marched Saturday from the Washington Monument to the Martin Luther King Jr. Memorial, seeking to bring attention to issues such as immigration, police brutality and affordable health care.

The rally, led by the Rev. Al Sharpton and his National Action Network, was sparked by concerns about President-elect Donald Trump’s stance on civil rights issues. Holding umbrellas in 30-degree temperatures, marchers stretched three city blocks as they progressed down Independence Avenue as part of the Martin Luther King holiday weekend celebration. “What do we want? Justice! When do we want it? Now!” they shouted, along with chants of “No justice, no peace!”

Dozens of speakers rallied attendees to focus attention on issues affecting African Americans, who made up the majority of the demonstrators. Topics included protecting voting rights, supporting affordable health care and working against mass incarceration and police brutality. But other speakers — including various Hispanic elected leaders, white labor-union officials, and representatives of the lesbian, gay, bisexual and transgender community — also called for unity among the groups in pushing for more affordable housing and supporting immigrants, labor unions, gay rights and equal pay for women.

Holding the rally a week before Trump’s Jan. 20 inauguration, organizers said, was intended to send a message to the incoming president and his administration, as well as to members of Congress, that the various groups plan to unify in the coming months and years to push for those causes.

“We can’t be divided. They are coming after all of these issues. We have to be as one, together,” shouted the Rev. Shane Harris, founder of the San Diego chapter of the National Action Network.

The march was entitled “We Shall Not Be Moved” after the Negro spiritual that became a civil rights folk song during the 1960s. Before the march began, Sharpton stood on a stage at the base of the Washington Monument in the shadow of the Smithsonian’s new National Museum of African American History and Culture.

Sharpton said that given dreary weather forecasts, rally organizers initially thought about canceling the march but decided to press on. “We are not fair-weather activists. We march in snow and the rain,” he said.

Sharpton joked that the weather forced him to wear a hat that covered his trademark salt-and-pepper locks. “I put on a hat and covered up my hair, something I haven’t done in a long time,” he said as the crowd cheered.

Sharpton said the rally was the first of what he called “House calls” to members of Congress in the next several days and weeks, mentioning visits on Capitol Hill following confirmation hearings.

“This is not a parade. This is a House call,” Sharpton said. “We come not to appeal to Donald Trump, because he’s made it clear what his policies are and what his nominations are. We come to say to the Democrats in the Senate and in the House and to the moderate Republicans to ‘Get some backbone. Get some guts. We didn’t send you down here to be weak-kneed.’ ”

One speaker elicited boos from the crowd during the rally, which lasted more than four hours. Lenora Fulani, who ran for president in 1988 and 1992 as a third-party candidate, told the crowd she did not vote in the presidential election out of disagreement with Democratic nominee Hillary Clinton.

“More than a million African Americans chose not to vote this year because we remembered how the Clinton administration affected black households with mass incarceration and the decline of the middle class. So there was a significant drop in voting among African Americans,” Fulani said.

Many in the crowd said they were angered by Fulani’s comments. “I am outraged. We are out here because so many people like her decided to stay home [on Election Day],” said Mary C. Williams, 56, an attorney in the District.

Several marchers began shouting “Black Lives Matter” and “I can’t breathe” as the stage was taken by Sybrina Fulton, mother of Trayvon Martin, the unarmed Florida teenager shot to death in 2012. She was joined by Gwen Carr, mother of Eric Garner, who died during a police arrest in 2014 in New York. The women called for police reform. “When my child was shot down, it caused me to stand up. We need to look after young people,” Fulton said.

D.C. Mayor Muriel E. Bowser (D) told the crowd that the nation was looking to Washington as an example. She also used the rally to champion statehood. “We are committed to justice and equality,” she told the crowd.

Several speakers tried to encourage those upset by the Trump election to use their anger as motivation.

“If you’re in the bed and depressed over the election, get out of that bed and do something,” said attorney Barbara Arnwine, founder of the Transformative Justice Coalition. “We got to fight. In four years, we will have another president. The people’s president, not no Russian hacking.”

Attendees from California, Arizona, New York and North Carolina flew, drove or came by bus. The only bright colors piercing the gray day were on umbrellas and hats — shades of blue, purple and pink marchers wore to represent their historically black fraternities and sororities.

The march was not the only demonstration to draw crowds to the nation’s capital Saturday. Thousands more gathered inside the historic Metropolitan African Methodist Episcopal Church downtown for the separate “We Are Here to Stay” rally in support of undocumented immigrants.

About 2,500 people packed the church where Frederick Douglass once urged his audience to “recognize that the rights of the humblest citizen are as worthy of protection as are those of the highest.”

More than a century later, the scene was at once festive and fearful. A mix of immigrants, activists and union members chanted, waved signs and sang folk songs in English and Spanish. The Howard Gospel Choir of Howard University sang, and a Latin band accompanied dancers twirling batons.

Several undocumented immigrants took the stage and vowed to defy Trump, who, as a candidate, pledged to deport the more than 11 million people in the country illegally. “I’m undocumented, unapologetic, unafraid, and I’m here to stay,” said Max Kim, 19, a Korean immigrant from Annandale, Va.

“We are not going to let Donald Trump or anyone else turn back the clock on social justice in the United States of America,” said Sen. Chris Van Hollen (D-Md.).

Many in attendance, however, felt anxiety about the next four years.

“My son is afraid his parents are going to be taken away from him,” said Lourdes Ortega, 27, an undocumented immigrant from Ecuador who lives in Baltimore. Under Obama, Ortega came forward to apply for deferred action from deportation — something that now could be used against her by a Trump administration.

“I don’t believe he will deport all of us,” she said of the president-elect. “But he could.”

Perry Stein contributed to this report.