The US House of Representatives has voted to ban so-called "partial birth" abortions, one of the most contentious issues in the country's abortion debate.
Abortion is a contentious issue in the US
The US Senate voted in favour of a ban on the form of abortion in March, and US President George W Bush is expected to sign the ban into law.
Anti-abortion groups have hailed the decision as protecting foetus rights.
However abortion-rights groups say that the move is an assault on human rights, and say they will challenge the prospective law in the nation's courts.
The House approved the measure by a vote of 282-139 on Wednesday night.
Partial birth abortions usually take place during the fifth or sixth month of pregnancy.
President Bush is taking the first step in banning all abortion procedures and ultimately banning abortion
Naral Pro-Choice America President Kate Michelman
The procedure involves the extraction of the body of the foetus into the vagina before the contents of the skull are suctioned and the intact foetus is removed from the woman's body.
Mr Bush has expressed his opposition to the procedure, calling it "an abhorrent procedure that offends human dignity".
Backers of the bill say the procedure is a form of infanticide.
"I cannot think of a more heinous, disturbing procedure that must be banned once and for all," Republican congressman Mark Foley told French news agency AFP.
"The time to end this monstrosity is long overdue."
However opponents say that the wording of the bill is open-ended enough that other forms of abortion could also be considered unlawful.
They argue that it does not allow exemptions for a woman's health, a caveat cited by former US President Bill Clinton who twice vetoed similar legislation.
Opponents also point to the Supreme Court's landmark decision Roe v Wade in 1973, which guarantees abortion rights.
"President Bush is taking the first step in banning all abortion procedures and ultimately banning abortion," Kate Michelman, president of Naral Pro-Choice America, told the Associated Press news agency.
"This is really serious."
The House version of the bill must now be reconciled with the Senate's by a conference committee.
The Alan Guttmacher Institute has found that, of 1.3 million abortions performed in the US in 2000, 2,200 were "partial-birth" abortions.