The Oklahoma state legislature has passed a bill banning abortions from the moment of fertilisation, with some exceptions, the strictest ban so far in the United States.
The action by Oklahoma follows steps taken in other Republican-led states to restrict access to abortions in anticipation of the US Supreme Court soon overturning Roe v Wade, the 1973 landmark decision allowing nation-wide access to abortion.
The bill now heads to the desk of Governor Kevin Stitt, a Republican, who is expected to sign it - at which point it would immediately come into effect.
Democratic Vice President Kamala Harris condemned the new law in a tweet, saying it is "the latest in a series of blatant attacks on women by extremist legislators".
Today, Oklahoma passed a law effectively banning abortion from the moment of fertilization—the latest in a series of blatant attacks on women by extremist legislators. It has never been more urgent that we elect pro-choice leaders at the local, state, and federal level.— Vice President Kamala Harris (@VP) May 19, 2022
Other Republican-led states such as Florida, Mississippi, and Texas have all enacted laws that previously would have been rejected by the Supreme Court under its Roe v Wade precedent, but a new conservative majority seems likely to now permit them.
Of the nine justices on the highest US court, six are conservative - three of whom were appointed by former president Donald Trump, who promised to only pick jurists who would overturn the nearly 50-year Roe v Wade precedent.
The Oklahoma legislation uses a novel enforcement procedure first enacted by Texas, which allows private citizens - not the state - to sue anyone who "performs or induces an abortion," or "aids or abets" someone seeking an abortion.
The person filing suit under the new law would receive a minimum of $10,000 (€9,443) for each abortion performed, as well as court costs and attorney fees.
The Oklahoma bill includes exceptions for instances of rape or incest, but requires that they be first reported to authorities.
It also allows exceptions for pregnancies that pose a risk to the life of the mother.
Oklahoma had also followed in Texas's footsteps last month, by enacting a law banning abortions after a heartbeat can be detected, usually around six weeks into pregnancy.
Earlier this month, a highly uncommon leak of a draft Supreme Court decision showed that the conservative justices were considering outright overturning Roe v Wade, in favour of state-by-state legislating on the matter.
That leak prompted protests across the country, and promises by Democrats to make access to abortion a key part of their electoral campaign in the November midterm elections.
"It has never been more urgent that we elect pro-choice leaders at the local, state, and federal level," Ms Harris said in her tweet, echoing similar calls by President Joe Biden and Democratic congressional leaders.
The Supreme Court's final decision should be known by the end of June.