President Donald Trump's administration on Monday pushed forward in defending U.S. rules easing access to the abortion drug mifepristone from a legal challenge that began during Democratic former President Joe Biden's administration.

The U.S. Department of Justice in a brief filed in Texas federal court urged a judge to dismiss the lawsuit by three Republican-led states on procedural grounds.

While the filing does not discuss the merits of the states' case, it suggests the Trump administration is in no rush to drop the government's defense of mifepristone, used in more than 60% of U.S. abortions.

Missouri, Kansas and Idaho claim the U.S. Food and Drug Administration acted improperly when it eased restrictions on mifepristone, including by allowing it to be prescribed by telemedicine and dispensed by mail.

The Justice Department and the office of Missouri Attorney General Andrew Bailey did not immediately respond to requests for comment.

Trump said while campaigning last year that he did not plan to ban or restrict access to mifepristone. Health and Human Services Secretary Robert F. Kennedy Jr. told Fox News in February that Trump has asked for a study on the safety of abortion pills and has not made a decision on whether to tighten restrictions on them.

Last year, the U.S. Supreme Court rejected a bid by anti-abortion groups and doctors to restrict access to the drug, finding that they lacked legal standing to challenge the FDA regulations.

Those plaintiffs dropped their case after the high court ruling, but U.S. District Judge Matthew Kacsmaryk, a Trump appointee, allowed the states to intervene and continue to pursue the lawsuit.

The U.S. Justice Department moved to dismiss their claims days before Trump took office in January.

In Monday's filing, government lawyers repeated their arguments that Texas is not the proper venue for the lawsuit and that the states lack standing to sue because they are not being harmed by the challenged regulations.

"Regardless of the merits of the States’ claims, the States cannot proceed in this Court," they wrote.

The three states are challenging FDA actions that loosened restrictions on the drug in 2016 and 2021, including allowing for medication abortions at up to 10 weeks of pregnancy instead of seven, and for mail delivery of the drug without a woman first seeing a clinician in-person. The original plaintiffs initially had sought to reverse FDA approval of mifepristone, but that aspect was rebuffed by a lower court.

The Republican-led states have argued they have standing to sue because their Medicaid health insurance programs will likely have to pay to treat patients who have suffered complications from using mifepristone.

They have also said they should be allowed to remain in Texas even without the original plaintiffs because it would be inefficient to send the case to another court after nearly more than two years of litigation.