WASHINGTON — Thousands of protesters marched at rallies in Washington and in cities across the country Saturday, denouncing Texas’s recent ban on most abortions and warning that the U.S. Supreme Court’s conservative majority could impose further restrictions in the coming months.

Amassing in downtown of the District of Columbia before walking in a clamorous procession to the Supreme Court, a roster of speakers bemoaned a looming threat to Roe v. Wade and implored Americans to enlist in a nationwide campaign to preserve women’s abortion rights.

“No matter where you live, no matter where you are, this moment is dark — it is dark — but that’s why we’re here,” Alexis McGill Johnson, president of Planned Parenthood, told the crowd at the “Rally for Abortion Justice.”

“It is our job to imagine the light even when we can’t see it,” Johnson said. “It is our job to turn pain into purpose. It is our job to turn pain into power.”

By 1 p.m., the crowd had swelled to the thousands as people spilled into the streets on either side of Freedom Plaza, clustering in pockets in the shade, their eyes on the stage.

“Not only is abortion health care, but at my organization we also believe it’s self-care,” Marsha Johns, executive director of the Ayiha Center, a Texas-based abortion rights organization, told the throng. “You can no longer tell us what to do with our bodies.”

At that, the protesters erupted in cheers, many hoisting homemade signs and chanting, “Abortion is healthcare!”

The day of demonstrations, organized by the Women’s March, was the first the group has sponsored since former president Donald Trump left office in January. Trump’s 2016 election catalyzed the first Women’s March, which drew millions of protesters to Washington and around the country and is widely considered the largest single-day demonstration in the country’s history, inspiring people to become first-time protesters, activists and politicians.

Attendance at subsequent marches has declined. But organizers are hoping to energize the movement around threats to Roe v. Wade, the 1973 Supreme Court case that protects a person’s right to an abortion. With a 6-3 conservative majority on the high court, many now fear that Roe could be in jeopardy.

In addition to the protest in Washington, organizers said they planned more than 600 demonstrations across the country, including New York City, where thousands could be seen marching across the Brooklyn Bridge toward Foley Square.

In downtown Chicago, where several thousand abortion rights protesters gathered, Kathy Flora, 50, said the Texas ban compelled her to travel in from the suburbs to attend her first demonstration. “I just can’t believe it’s gotten to this point, to be honest,” she said. “I thought it was supposedly settled law.”

At a protest in Jackson, Miss. a group of women in their 60s questioned whether younger women would fully grasp the consequences of Roe being overturned. Lisa White, 65, who traveled 170 miles from her home in Bay St. Louis, Miss., said the way women’s rights are being “slashed across the board” evokes reminders of her youth when she said her aspirations of going to law school were dismissed by men who thought “women should be barefoot and pregnant.”

“I was not taken seriously,” said White, who attended law school in Connecticut. “I had to fight for everything I got.”

In San Francisco, the thousands of marchers along Market Street included Jessie Reynolds, 20, a student who said she began to follow politics only recently after becoming aware of the Black Lives Matter movement.

“That was my ‘coming to Jesus’ moment,” she said. Referring to the abortion rights movement, she said she hoped the march would “put the fire back in women. I wasn’t a part of this fight up until this year and I’m hoping that a lot of other people have turned that switch on.”

As the day’s events began into downtown Washington, people streamed into Freedom Plaza from across the region and beyond, many of them mothers and daughters arriving together for what they said was their first protest.

“I’m hoping my kids won’t have to protest for their bodies,” said Katie Donovan, 18, who arrived from Maine wearing a red tank top that read, “Keep Your Laws Off My Body.” Her mother, Katrina Marianacci, 48, stood nearby with her other daughter, the two of them also wearing the same tank top, said she wanted the girls to “see what happens when women come together to fight for their rights.”

Lisa Santoro, who lives outside Philadelphia, drove to the rally in Washington with her two adult daughters, Molly and Abby. As a high school student in the 1980s, Santoro said she never feared that she would lose her legal right to an abortion.

Now she worries her daughters won’t have the same access. “Maybe we should have been out here marching for reproductive rights all along,” she said.

The demonstration also drew hundreds of antiabortion protesters, including a couple of dozen who sought to disrupt a morning faith service hosted by abortion activists at Freedom Plaza.

“Woe to you!” one man protesting abortion yelled. “The blood of innocent babies is on your hands!”

To drown him out, the crowd erupted in singing and clapping, as one woman, Angela Jamison, 51, of Fairfax, Va., stepped in to point him back across the street where the counterdemonstrators were supposed to stay.

After the speeches at Freedom Plaza, thousands of protesters marched along Pennsylvania Avenue, led by an all-female drum line and chanting, “My body! My choice!”

At the Supreme Court, they were met by another group of counterprotesters who greeted them with a banner that read “We are the pro-life generation.”

“Abortion harms women!” the counterprotesters chanted as a live band played Christian rock.

“We’re leading what should be the true message of a women’s march,” said Michele Hendrickson, 35, the director of strategic initiatives for Students for Life of America. “If we want to talk about women empowerment, then we shouldn’t be feeding women a lie that they need abortion to succeed.”

Alveda King, an evangelical minister and antiabortion activist who is the niece of Martin Luther King Jr., stood in front of the Supreme Court and prayed. “We are crying out for the babies,” King said. “What you’ve done in Texas, do it across the country.”

As the march ended outside court, protesters and counterprotesters exchanged chants — “Pro- life! Pro women!” one side shouted, “My body! My choice!” the other side countered — until U.S. Capitol Police officers separated them.

On Sept. 1, Texas’s law state went into effect prohibiting abortion once cardiac activity is detected, around six weeks gestation, before most people know they are pregnant. Under the law, citizens can sue anyone that helps facilitate an illegal abortion in Texas, from the doctor who performs the procedure to an Uber driver who drives a patient to a clinic.

The Supreme Court on Dec. 1 is to consider the constitutionality of a Mississippi law that bans abortions after 15 weeks gestation, nearly 10 weeks before a fetus can survive outside the uterus. Roe v. Wade protects the right to an abortion before the point of fetal viability. If the law is allowed to stand, it will further empower other states to pass similar restrictions.

Recent polls show Americans oppose overturning Roe v. Wade by a roughly 2-to-1 margin. A large majority of Americans also support allowing a person to receive an abortion in the case of rape or threats to her health.

Abortion advocates were happy to see the words “abortion” included in the name of the March, said Aimee Arrambide, the executive director of Avow, an abortion rights group in Texas.

“There is stigma surrounding abortion, even from people who support abortion access,” she said.

The title of the March is a nod to the reproductive justice movement, founded by women of color, which advocates not just for abortion to be legal, but accessible to all, regardless of socio-economic status or any other barrier that might cut someone off from the procedure.

Rachel O’Leary Carmona, executive director of the Women’s March, described the movement as a coalition of more than 120 groups, including Planned Parenthood and Black Feminist Future, focused on ensuring women are able to safely and legally access abortion and health care for their families.

“Roe is the floor, not the ceiling,” Carmona said. “Abortion rights, reproductive justice, is absolutely a part of voting rights and justice for immigrants, and racial justice because they can’t be extracted from themselves. The most impacted communities across all those groups are communities of color.”

Yet to some Black feminists, the rally seemed like a “White woman’s march,” as 24-year-old Devonn Thomas put it, saying there needed to be more focus on disparities that hurt minority women’s access to abortion.

Thomas, who identifies as queer, said that she is the daughter of a queer mother too, and that her mother always taught her the importance of the right to choose. But that choice, she said, has always been easier for wealthier White women while minority women have faced barriers.

“Abortion rights is still white power if it’s not given to Black people as well,” Thomas said.

The Washington Post’s Donovan Thomas, Sarah Thomas, Ellie Silverman and Scott Clement contributed to this report.