Democratic 2020 U.S. presidential candidate and former Vice President Joe Biden speaks during a campaign stop in Philadelphia, Pennsylvania, U.S., May 18, 2019.

Joe Biden's stance on abortion came under attack on Wednesday after his campaign confirmed that the former vice president still supports the controversial Hyde Amendment, passed more than 40 years ago, that bars federal funding of abortion except in cases of rape, incest or when the life of the mother is at risk.

Biden's position is consistent with the views he held while serving in the Senate. But it marks a departure from much of the sprawling Democratic field, as well as the official party platform adopted in 2016. That distinction could pose some trouble for the Pennsylvania native, who is making his case to Democratic voters while a conservative Supreme Court and restrictive state abortion laws fuel opposition within his party to anti-abortion measures.

"He has not at this point changed his position on the Hyde Amendment," the Biden campaign said in a statement. "The Hyde Amendment does not prevent organizations in the US that provide lifesaving health care services for women from receiving the federal funding they need. But given the current draconian attempts to limit access to abortion, if avenues for women to access their protected rights under Roe V Wade are closed, he would be open to repeal."

Biden's continued support of the Hyde Amendment, first reported by NBC News, comes about a month after Biden told an ACLU volunteer that he opposed the amendment.

"It can't stay," Biden said May 4 in South Carolina. The volunteer asked if Biden was in favor of abolishing the amendment, and Biden said that he was.

ACLU video

The Biden campaign said that he "misheard the woman on the ropeline and thought she was referring to the Mexico City rule, which prevents federal aid money from going to organizations overseas that perform abortions."

The Mexico City rule, a Reagan-era policy that prevents federal aid money from funding abortion providers overseas, was rescinded by both Democratic presidents elected after it first came into effect, and re-instituted by both Republicans.

Top reproductive rights groups, including Planned Parenthood, NARAL and EMILY's List, slammed the campaign's position on the Hyde Amendment. Because the Hyde Amendment largely affects women on Medicaid, the groups say that Biden's stance disproportionately hurts poor and minority women.

"There's NO political or ideological excuse for Joe Biden's support for the Hyde Amendment," wrote NARAL, an advocacy organization, in a post on Twitter. "His position further endangers people already facing enormous hurdles."

In a statement, Jamal Brown, a Biden spokesman, wrote that "Joe Biden firmly believes that Roe v. Wade is the law of the land and should not be overturned."

"Throughout his career, Joe Biden has fought vigorously to protect a woman's right to choose and against measures criminalizing abortion. As Chairman of the Judiciary Committee, he blocked the Supreme Court nomination of Judge Robert Bork and he opposed anti-choice justices Roberts, Alito, and Thomas," Brown wrote.

But Biden's Democratic rivals wasted little time in trying to highlight his isolation on the Hyde Amendment.

"No woman's access to reproductive health care should be based on how much money she has. We must repeal the Hyde Amendment," wrote Sen. Kamala Harris of California, in a post on Twitter.

"There is #NoMiddleGround on women's rights. Abortion is a constitutional right. Under my Medicare for All plan, we will repeal the Hyde Amendment," Sen. Bernie Sanders of Vermont wrote on the social media platform.

"Clearly I think the Hyde Amendment is wrong," Sen. Cory Booker of New Jersey told reporters.

"The Hyde Amendment should not be American law," Sen. Elizabeth Warren of Massachusetts said, according to The New York Times.

But Biden's stance earned some plaudits from anti-abortion groups.

"It should not be a controversial stance to oppose public funding of optional procedures, and in fact it should be a common American value that, because abortion is always the deliberate, intentional, and forcible ending of a human life, it should be unthinkable," Tom Shakely, a spokesperson for Americans United for Life, said in a statement.

"However, in today's partisan and polarized climate, we're grateful for Mr. Biden's continuing support of the Hyde Amendment, even as we express skepticism of his ability to maintain this position in the face his radical and extremist fellow contenders in the Democratic presidential race," Shakely said.