Protesters on both sides of the U.S. abortion debate faced off with chants, prayers and signs outside the Supreme Court on Tuesday, hours after the leak of a draft opinion that would overturn the court's landmark 1973 Roe v. Wade decision.

Demonstrators on the sidewalk just beyond the barricaded marble steps of the courthouse across from the U.S. Capitol, growing from dozens of people to hundreds, boisterously but peacefully voicing a mix of support for and opposition to ending a constitutional right to abortion nationwide.

Several dozen anti-abortion activists dominated the protests early in the day, beating on drums and chanting through megaphones: "Pro-choice is a lie, babies never choose to die," and "Abortion is violence, abortion is oppression."

Some knelt in prayer.

One man wearing a pink sweatshirt in support of Roe v. Wade tried in vain to tamp down the chants of an anti-Roe protester by holding his hand over her megaphone.

Abortion rights advocates shouted back, "Off our bodies" and "abortion saves lives." Others held signs reading, "Abortion is healthcare" and "Abortion is not a dirty word." One sign displayed by a group identifying as Roman Catholics supporting abortion access said: "Thou shalt not steal my civil rights."

But by late afternoon, a larger and growing assembly of hundreds of abortion rights demonstrators held sway.

"It makes me very afraid. I feel very sorry for ... young women. You're starting all over again," Roe v. Wade supporter Paula Termini, 70, a nurse who has worked in delivery rooms and Planned Parenthood clinics, told Reuters outside the court. "It's going to take a long time to get those gains back again."

Fellow abortion rights advocate Chelsea White imagined a widespread return to "back-alley abortions," saying that by allowing states to deny access to medically safe procedures, "All they're doing is sacrificing women's health."

It appeared the protests in Washington were a prelude to mass rallies planned by abortion rights advocates for later in the day in cities across the country, including Atlanta, Chicago, Los Angeles, New York and Philadelphia.

Several hundred demonstrators demanding the protection of rights for women to end their pregnancies assembled early in the evening in lower Manhattan's Foley Square, waving signs with such slogans as "Bans Off Our Bodies" and "Abortion is Freedom."

The national Women's March organization urged supporters to bring their families and signs to afternoon demonstrations at "courthouses and federal buildings everywhere," promoting the social media hashtag #BansOffOurBodies."

One of the more colorful acts of anti-abortion protest earlier in the day emerged in San Francisco, where a man calling himself the "Pro-Life Spiderman" scaled a downtown skyscraper while posting video footage of his climb on Instagram. Local news media reported the man was taken into custody by city police.