The U.S. Supreme Court should restrict the availability of the abortion pill mifepristone, anti-abortion groups challenging the medication’s federal regulatory approval told the justices in a filing on Tuesday, urging them to implement curbs ordered by a conservative federal judge in Texas.

The challengers urged the Supreme Court to reject emergency requests by Democratic President Joe Biden’s administration and the pill’s manufacturer to halt the April 7 preliminary injunction issued by U.S. District Judge Matthew Kacsmaryk in Amarillo that would greatly limit mifepristone’s distribution, while litigation proceeds.

The New Orleans-based 5th U.S. Circuit Court of Appeals on April 12 declined to block the restrictions but halted a part of Kacsmaryk’s order that would have suspended the U.S. Food and Drug Administration (FDA) approval of the drug that was given in 2000, effectively pulling it off the market. The FDA is the U.S. agency that signs off on the safety of food products, drugs and medical devices.

The case poses another major threat to abortion rights in the United States in the aftermath of the Supreme Court’s decision last June to overturn the landmark 1973 Roe v. Wade ruling that had legalized the procedure nationwide. Mounting abortion bans and restrictions have been enacted by Republican-led states since then.

Mifepristone is taken with another drug called misoprostol to perform medication abortion, which now accounts for more than half of all U.S. abortions.

Conservative Justice Samuel Alito, who authored the June ruling, last Friday temporarily blocked the restrictions on mifepristone in order to give the Supreme Court time to weigh the requests by the administration and Danco Laboratories, along with the challengers’ arguments. The Supreme Court has a 6-3 conservative majority.

Alito, who handles emergency matters arising in a group of states including Texas, delayed the restrictions from taking effect until 11:59 p.m. EDT (0359 GMT) on Wednesday. The court would be expected to issue another order on the issue by that time.

In a case that could undercut federal regulatory authority over drug safety, the administration and Danco on Friday said that mifepristone might not be available for months if the restrictions are allowed to take effect.

Kacsmaryk’s decision conflicted with an order also issued April 7 in a separate case from Washington state directing the FDA to keep mifepristone available in 17 states and the District of Columbia, raising questions over how the FDA would manage contradictory commands from the judiciary if the Supreme Court denies the administration’s bid for relief.

Anti-abortion groups led by the recently formed Alliance for Hippocratic Medicine and four anti-abortion doctors sued the FDA in November seeking to reverse approval of mifepristone.

The FDA asserts that mifepristone is safe and effective, a record that it has said is conclusively demonstrated over decades of use by millions of Americans and that adverse effects of mifepristone are exceedingly rare.

The restrictions set by the lower courts would restore curbs on mifepristone that had been lifted since 2016 as the FDA steadily expanded access. These restrictions would include a requirement for three in-person doctor visits to obtain mifepristone and would limit its use to the first seven weeks of pregnancy, down from the current 10.

Since last year’s Supreme Court decision, 12 U.S. states have put in place outright bans while many others prohibit abortion after a certain length of pregnancy. The latest Republican-led move came in Florida, where Governor Ron DeSantis on April 13 signed a new law that bans most abortions after six weeks of pregnancy.