WASHINGTON — The Biden administration will ask the Supreme Court to block a Texas law that bars most abortions after six weeks of pregnancy while a challenge to it moves forward, a Justice Department spokesman said on Friday.

A ruling by the U.S. Court of Appeals for the Fifth Circuit on Thursday kept in place its own previous order last week that had temporarily allowed the law to be enforced again, overturning a federal district judge in Austin who had temporarily blocked its enforcement.

“The Justice Department intends to ask the Supreme Court to vacate the Fifth Circuit’s stay of the preliminary injunction against Texas Senate Bill 8,” Justice Department spokesman Anthony Coley said in a statement.

The 2-to-1 decision by a three-judge appeals panel dealt the Biden administration a significant setback, as it seeks to undo a law that has virtually ended abortions in the state of Texas.

The Texas law, one of the strictest in the country, bans abortions when cardiac activity is detected, at around six weeks of pregnancy, a time when women may not yet know they are pregnant. It also makes no exceptions for rape or incest.

The law immediately stopped most abortions in Texas when it went into effect at the start of September, after the Supreme Court declined to intervene. Demand at clinics in nearby states like Oklahoma has surged as women in Texas seeking abortions after six weeks of pregnancy have been forced to travel out of state.

The Justice Department is suing Texas over the law’s unique enforcement mechanism, which it claims violates the Constitution by using by using private parties to enforce the law, rather then the state. This lets Texas technically comply with court decisions that say states many not prohibit abortion.

The law encourages private parties to bring lawsuits against anyone accused of performing or aiding in an abortion that violates the statute by granting $10,000 to plaintiffs that successfully sue.

Attorney General Merrick B. Garland called the enforcement mechanism an “unprecedented” effort to bar women from their constitutionally protected right to have an abortion.

The department argued in its lawsuit that the Texas law is invalid under the supremacy clause of the Constitution, which gives federal law precedence over state law, and under the equal protection guarantees of the 14th Amendment.

A federal district judge last week granted the department’s request to halt enforcement of the law while the legal challenge makes its way through the court system, delivering a short-lived win to the Biden administration. But two days later, the appeals panel intervened.