Abortion has become unavailable or severely restricted in a dozen US states since last week's Supreme Court ruling, abortion rights activists said Friday.

"Anti-abortion politicians and states across the country have taken the baton from the Supreme Court and have begun to enact abortion bans," said Anthony Romero, executive director of the American Civil Liberties Union (ACLU).

"As of this morning, abortion is unavailable or largely unavailable in approximately 12 states as a result of the Supreme Court's decision," Romero told reporters.

"That number is expected to grow in coming days, weeks and months until we reach approximately 26 states across the country," he said. "More than half the country will ban abortion."

The conservative-dominated Supreme Court last week eliminated 50 years of federal constitutional rights to abortion.

President Joe Biden denounced the ruling at a White House event on Friday, calling it a "terrible, extreme decision" that was "upending lives."

"I share the public outrage of this extremist court," Biden said.

Abortion rights activists protest outside the US Supreme Court
Abortion rights activists protest outside the US Supreme Court GETTY IMAGES NORTH AMERICA via AFP / TASOS KATOPODIS

Romero and leaders of other abortion rights groups said they planned to fight the bans in the courts, in state legislatures and at the ballot box.

The ACLU, Planned Parenthood Federation of America and Center for Reproductive Rights said they have taken legal action to block abortion bans in 11 states: Arizona, Idaho, Kentucky, Louisiana, Mississippi, Ohio, Oklahoma, Florida, Texas, Utah, and West Virginia.

The ACLU leader stressed the importance of electing politicians who will support abortion. "We must turn to the ballot box to restore abortion rights," he said.

In the meantime, Alexis McGill Johnson, CEO and president of Planned Parenthood, said the organization, the largest US abortion provider, has expanded capacity in "safe states" where abortion is legal.

"But the reality is the 24 states which we hope to see keep it legal over the next few months will never be able to absorb the needs of the entire country," she said.

Nancy Northup, CEO and president of the Center for Reproductive Rights, said the "immediate priority is to preserve access in every state for as long as we can."

"With abortion services stopping immediately in many states, this is just the beginning of what is a public health emergency," Northup said.

A CBS poll over the weekend found that a solid majority -- 59 percent -- of Americans and 67 percent of women disapproved of the court overturning the 1973 ruling in "Roe v. Wade" that enshrined a woman's legal right to abortion.