A US federal judge has temporarily blocked the near-total ban on abortion in Texas, dealing the first legal blow against the contentious law and throwing its future into uncertainty.

The law, known as Senate Bill 8, banned most abortions in the nation’s second-most populous state and, until now, had withstood a wave of early challenges.

Wednesday’s ruling, which stems from a challenge brought by the Biden administration, will prevent the state from enforcing the Republican-backed law while litigation over its legality continues. But even with the law on hold, abortion services in Texas may not instantly resume because doctors still fear that they could be sued without a more permanent legal decision.

“Tonight’s ruling is an important step forward toward restoring the constitutional rights of women across the state of Texas,” White House press secretary Jen Psaki said in statement late on Wednesday. “The fight has only just begun, both in Texas and in many states across this country where women’s rights are currently under attack.”

Texas officials are likely to seek a swift reversal from the fifth US circuit court of appeals, which previously allowed the restrictions to take effect.

The law, signed by Republican governor Greg Abbott in May, prohibits abortions once cardiac activity is detected, which is usually around six weeks, before someone can even know they are pregnant. To enforce the law, Texas deputized private citizens to file lawsuits against violators, and has entitled them to at least $10,000 in damages if successful.

The lawsuit was brought by the Biden administration, which has said the restrictions were enacted in defiance of the US constitution. The Biden administration argued that Texas has waged an attack on the constitutional right to abortion.

“A state may not ban abortions at six weeks. Texas knew this, but it wanted a six-week ban anyway, so the state resorted to an unprecedented scheme of vigilante justice that was designed to scare abortion providers and others who might help women exercise their constitutional rights,” said Brian Netter, justice department attorney, to the federal court on Friday.

In a 113-page opinion, judge Robert Pitman took Texas to task over the law, saying Republicans lawmakers had “contrived an unprecedented and transparent statutory scheme” to deny patients their constitutional right to an abortion.

“From the moment SB8 went into effect, women have been unlawfully prevented from exercising control over their lives in ways that are protected by the constitution,” wrote Pitman, who was appointed to the bench by Barack Obama.

“That other courts may find a way to avoid this conclusion is theirs to decide; this court will not sanction one more day of this offensive deprivation of such an important right.”

Abortion providers say their fears have become reality in the short time the law has been in effect. Planned Parenthood says the number of patients from Texas at its clinics in the state decreased by nearly 80% in the two weeks after the law took effect.

Some providers have said that Texas clinics are now in danger of closing while neighboring states struggle to keep up with a surge of patients who must drive hundreds of miles. Others, they say, are being forced to carry pregnancies to term.

Other states, mostly in the South, have passed similar laws that ban abortion within the early weeks of pregnancy, all of which judges have blocked. But Texas’ version has so far outmaneuvered the courts because it leaves enforcement to private citizens to file suits, not prosecutors, which critics say amounts to a bounty.

At least one Texas abortion provider has admitted to violating the law and been sued but not by abortion opponents. Former attorneys in Illinois and Arkansas say they sued a San Antonio doctor in hopes of getting a judge who would invalidate the law.

The Texas law is just one that has set up the biggest test of abortion rights in the US in decades, and it is part of a broader push by Republicans nationwide to impose new restrictions on abortion.

On Monday, the US supreme court begins a new term, which in December will include arguments in Mississippi’s bid to overturn 1973’s landmark Roe v Wade decision guaranteeing the right to an abortion.

Last month, the court did not rule on the constitutionality of the Texas law in allowing it to remain in place. But abortion providers took that 5-4 vote as an ominous sign about where the court might be heading on abortion after its conservative majority was fortified with three appointees from Donald Trump.

Ahead of the new supreme court term, Planned Parenthood on Friday released a report saying that if Roe v Wade were overturned, 26 states are primed to ban abortion. This year alone, nearly 600 abortion restrictions have been introduced in statehouses nationwide, with more than 90 becoming law, according to Planned Parenthood.

In a statement following Wednesday’s order, the organization tweeted: “It’s been 36 days since Texas deprived its citizens of their constitutional right to abortion. The relief granted by the court today is overdue. We will continue fighting this ban in court, until we are certain that Texans’ ability to access abortion is protected.”