Thousands of activists chanting, banging drums and wielding placards flooded streets across the United States on Saturday in a national day of action calling for safe and legal access to abortion.

The mass demonstrations were a response to a leaked draft opinion showing the Supreme Court's conservative majority is poised to overturn Roe v. Wade, a landmark 1973 ruling guaranteeing abortion access nationwide.

"Nobody has the right to make a decision on somebody else's body," said Hanna Williamson, 20, who drove three hours to join several thousand protesters in Washington.

Thousands more people assembled in a central square in Brooklyn, New York, to carry a giant pink banner that read: "Our Bodies. Our Futures. Our Abortions."

Thousands of people also rallied in Texas and Kentucky, with smaller events elsewhere in the country.