Initiatives by social conservatives to limit abortion inched forward in three southern US states this week, contributing to one of the most emotionally-charged debates in US politics.

In Florida, the House of Representatives voted 78-33 in favor of imposing a 24-hour waiting period on women seeking an abortion and requiring new abortion clinics to be owned by doctors.

The latter point would effectively ban Planned Parenthood, the biggest single provider of abortions in the United States, mainly to low-income women, from opening new facilities.

"This isn't an insidious war against women -- it's a righteous war for children," said Republican lawmaker James Grant in an impassioned debate Thursday, as the bill moved on to the state Senate for further debate.

A day earlier, Georgia's House of Representatives voted 102-65 for a "fetal pain" bill that would slash from 26 weeks to 20 weeks the period in which women could get elective abortions.

That time frame is based on what the bill calls "substantial evidence" that, 20 weeks after fertilization, an unborn child can feel pain. Doctors who break the law would risk up to 10 years in prison.

Doug McKillip, the bill's Republican sponsor, said it would "save 1,000 to 1,500 lives," but critics argued it amounts to lawmakers dictating what doctors can or cannot do.

"It is time for the government to get out of my examination room and my office," said obstetrician Ruth Cline, quoted in the Atlanta Journal Constitution newspaper.

Meanwhile, Virginia was on track to become the eighth state to mandate pre-abortion ultrasounds, after a toned-down version of a highly contested bill cleared its final legislative hurdle.

Like Florida and Georgia, Virginia's legislature is Republican controlled.

The Virginia House of Delegates approved a Senate-amended version of the "informed consent" bill by a 61-35 vote Thursday, leaving it in the hands of Governor Bob McDonnell to sign into law.

"The governor will act upon the bill within seven days of its delivery to him," his spokesman Jeff Caldwell told AFP by email Friday, adding that a firm signing date remains to be set.

In its original form, the bill triggered a national furor by insisting that abortions in Virginia be preceded by transvaginal ultrasounds, in which an electronic probe is inserted deep into a woman's vagina.

No other state with pre-abortion ultrasound laws, including Texas, call for such an invasive procedure.

Under fire from pro-choice activists, and ridicule from late-night TV comics, McDonnell -- a potential Republican candidate for vice president -- rejigged the bill so as to make only external abdominal ultrasounds mandatory.

State senators further amended the text to exempt rape and incest victims from ultrasounds, before sending it back to the House where its mainly Republican supporters and Democratic opponents locked horns one last time.

"I have trouble going to sleep at night" knowing that more than 54 million abortions have been carried out since abortion was ruled legal by the US Supreme Court in 1973, said House majority leader M. Kirkland Cox.

To which David Englin, a Democrat, riposted: "The true nature of this bill is to use emotional blackmail, practical logistical barriers and just plain old government bullying to try to prevent women from having abortions."

Among other southern states, Mississippi's Republican-dominated legislature is considering about two dozen bills and constitutional amendments to limit abortion, including ultrasound and fetal-pain bills.

Last year, a proposed change to the state constitution to grant personhood to unborn children -- effectively outlawing abortion -- was rejected by 58 percent of Mississippi voters.