The decision keeps in place a number of restrictions on access to abortion pill, used in about half of all US abortions.

Wednesday’s decision by US Supreme Court Justice Samuel Alito puts the issue on hold for two additional days, until Friday at 11:59pm US Eastern time (0359 GMT Saturday).

A previous decision to maintain access to mifepristone had been set to expire later on Wednesday.

While the conservative justice’s ruling means that patients will continue to be able to receive mifepristone in the short term, it also upholds limitations implemented by a lower court as litigation over the pill continues.

Anti-abortion groups are seeking to overturn the Food and Drug Administration’s approval of mifepristone, granted more than two decades ago in 2000.

On April 7, a Texas District Judge Matthew Kacsmaryk ordered the suspension of mifepristone, granting an anti-abortion lawsuit’s call for an injunction on the pill while the FDA’s decision was challenged in court.

Kacsmaryk gave the administration of President Joe Biden seven days to respond to the injunction before it took effect.

The Biden administration quickly appealed. On April 12, the New Orleans 5th Circuit Court of Appeals allowed mifepristone to stay on the market but reverted the rules governing its access to standards set in 2016.

Those standards allowed mifepristone to be used only up to seven weeks of pregnancy, not 10 as the FDA has subsequently allowed. They also bar mifepristone from being sent in the mail, as part of recent FDA guidelines to ease access.

The Biden administration challenged those limitations and had expressed confidence in recent days that the Supreme Court would take its side.

Alito’s decision is likely to heighten tensions in the US, where Republican efforts to restrict abortion access have surged following the court’s decision last June to repeal Roe v Wade, a 1973 case that had enshrined the constitutional right to abortion.