Demonstrators rally to demand continued access to abortion during the March for Reproductive Justice, Oct 2, 2021, in New York. (MARY ALAFFER/AP)

WASHINGTON/AUSTIN - Women marched by the thousands on Saturday on the Supreme Court, the Texas Capitol and cities across the United States to protest increasing state restrictions on abortion and advocate for maintaining a constitutional right to the procedure.

The 660 demonstrations around the United States were largely sparked by a Texas law that bans abortions after about six weeks of pregnancy. The measure, which went into effect last month, is the most restrictive in the country.

READ MORE: Texas moves ahead with restrictive abortion law

“No matter where you live, no matter where you are, this moment is dark,” Alexis McGill Johnson, president of Planned Parenthood, told the crowd at the “Rally for Abortion Justice” in Washington.

In the Texas capital of Austin, hundreds gathered in sweltering heat to denounce the so-called "heartbeat" law signed by Governor Greg Abbott. It bans abortion after cardiac activity is detected in the embryo, usually around six weeks. That is before most women know they are pregnant and earlier than 85 percent to 90 percent of all abortions are carried out, experts say. 

Pro-abortion rights demonstrators take part in a Women's March in Chicago on Oct 2, 2021. (MARK CAPAPAS/AP)

The law relies on ordinary citizens to enforce the ban, which makes no exceptions for rape or incest, rewarding them at least $10,000 if they successfully sue anyone who helped provide an illegal abortion.

We're heading in the wrong direction. It's the tyranny of the minority.

 Katy Allen, a 67-year-old university researcher from Rochester, New York

Some of the demonstrators said the law would backfire on legislators. "I think more people believe in the issue of providing safe abortions than our legislature realizes," said Andrea Roberts, 49, an Austin preschool director.

"Abort Abbott" appeared on several of the demonstrators' signs and T-shirts, while others sported the Texas state slogan, "Come and Take It" next to a drawing of a uterus.

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Washington protesters marched to the US Supreme Court two days before the court reconvenes for a session in which the justices will consider a Mississippi case that could enable them to overturn abortion rights established in the landmark 1973 Roe v. Wade case.

If the court overturns the precedent, abortion access would no longer by protected by the Constitution, leaving states free to ban it, limit it or allow it without restrictions.

The justices, in a 5-4 decision on Sept 1, already denied a request from abortion and women's health providers to block enforcement of the Texas law.

People attend the Women's March ATX rally, Oct 2, 2021, at the Texas State Capitol in Austin, Texas. The march was a response to controversial legislation recently passed by Texas lawmakers which has banned most abortions in Texas. (STEPHEN SPILLMAN/AP)

"It's cruel and it's sure as hell not Christian," Kenya Martin, of the nonprofit Abortion Care Network told several thousand Washington protesters.

Under sunny skies, the demonstrators carried signs that said, "Bans off my body," "Think outside my box" and "Keep your rosaries off my ovaries."

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"We're heading in the wrong direction," said Katy Allen, a 67-year-old university researcher from Rochester, New York. "It's the tyranny of the minority."

About two dozen counter-protesters also showed up to press their case in support of anti-abortion laws.

A rally and march in New York drew thousands of protesters, including actresses Amy Schumer and Jennifer Lawrence

"We want to call on everyone to respect life," said Albert Stecklein, a 56-year-old business administrator from Rockville, Maryland. "The child in the womb is no less deserving of respect and dignity than you or me."

Rachel O'Leary Carmona, executive director of Women's March, said the number of marches would be second only to the group's first protest, which mobilized millions of people around the world to rally against former US president Donald Trump the day after his inauguration in 2017.

A rally and march in New York drew thousands of protesters, including actresses Amy Schumer and Jennifer Lawrence.

Abortion rights advocates and the US Justice Department have challenged the Texas law in state and federal courts, arguing that it violates Roe v. Wade.

A federal judge in Austin on Friday heard the Justice Department's request to block the law temporarily while its constitutionality is challenged.