About half of the US states are moving immediately to either ban or severely restrict abortion, responding to decades of activism by the what is known as the "pro-life" movement.

With the ruling, the Supreme Court has made the United States an
With the ruling, the Supreme Court has made the United States an "outlier" in the world, President Biden said. (AFP)

US President Joe Biden has criticised the Supreme Court ruling overturning the landmark Roe v. Wade decision on abortion, saying the health and life of American women are now at risk.

"It's a sad day for the court and for the country," Biden said in a White House address after Friday's ruling struck down decades of constitutional protection of abortion. 

Biden promised to go on fighting for reproductive rights but said no executive order can guarantee a woman’s right to choose. He urged voters to send lawmakers to Congress who will work to codify abortion rights as the law of the land.

Biden made a point of calling for any protests to remain peaceful. "No intimidation. Violence is never acceptable," he said.

The court has done what it has never done before — expressly take away a constitutional right that is so fundamental to so many Americans

US President Joe Biden

As reactions poured in, Canadian Prime Minister Justin Trudeau described the ruling as "horrific", while British Prime Minister Boris Johnson called it a "big step backwards".

UN human rights chief Michelle Bachelet said the decision to end the right to abortion is "a huge blow to women's human rights and gender equality".

"Access to safe, legal and effective abortion is firmly rooted in international human right law and is at the core of women and girls' autonomy and ability to make their own choices about their bodies and lives," Bachelet said in a statement.

READ MORE: Thousands demonstrate across US against scrapping abortion rights

Divergent views

On the other side of the spectrum, former US president Donald Trump said "God made the decision", after the seismic ruling on one of America's most divisive issues.

"This is following the Constitution, and giving rights back when they should have been given long ago," Trump told Fox News.

Asked if he felt he played a role after appointing three conservative justices to the court while in office, he said "God made the decision".

The Vatican's Academy for Life praised the Supreme Court's decision, saying it "challenges the whole world" on life issues.

The Vatican department also said in a statement that the defence of human life could not be confined to individual rights because life is a matter of "broad social significance".

Three liberal West Coast states, meanwhile, banded together to issue a joint pledge to defend abortion rights.

"The governors of California, Oregon and Washington today issued a Multi-State Commitment to defend access to reproductive health care, including abortion and contraceptives, and committed to protecting patients and doctors against efforts by other states to export their abortion bans to our states," a statement said.

The three, all Democrats, released a video message which they said was intended to underline that the West Coast will "remain a place where reproductive health care will be accessible and protected".

On the other hand, the Midwestern conservative state of Missouri became the first US state to ban abortion, hours after the Supreme Court ruling.

"Missouri has just become the first in the country to effectively end abortion," state attorney general Eric Schmitt said on Twitter. "This is a monumental day for the sanctity of life."

READ MORE: US state of Oklahoma brings 'pro-life' abortion law

Source: TRTWorld and agencies