The state measure, which went into effect on Sept. 1, bars physicians from knowingly performing an abortion if there is “a detectable fetal heartbeat,” including embryonic cardiac activity that appears about six weeks into a pregnancy.

The Texas ban, which doesn’t make exceptions for rape or incest, conflicts with current Supreme Court precedent, but it has presented unique challenges in litigation. The Justice Department sued the state in a federal court in Austin last week after legal efforts by abortion clinics to block the law before it went into effect failed.

The law has proved difficult to challenge in court because it delegates enforcement to private citizens rather than government officials. The law authorizes damages of $10,000 or more to anyone who successfully sues a defendant accused of performing or aiding in an abortion.

Earlier this month, the Supreme Court by a 5-4 vote declined to block the Texas law after it was challenged by abortion providers, citing procedural uncertainties over the proper defendant. Chief Justice John Roberts and three more-liberal justices dissented, saying the law should have been placed on hold while the court examined the measure and its unique enforcement structure.

In legal papers, the Justice Department said the procedural hurdles that might interfere with a private plaintiff’s suit weren’t applicable to the federal government.

Attorney General Merrick Garland, in announcing the Justice Department lawsuit last week, accused Texas of engaging in a scheme “to nullify the Constitution.”

The department announced last week that it would be requesting the kind of preliminary relief that it formally sought with Tuesday’s emergency motion.

The office of Texas Attorney General Ken Paxton didn’t immediately respond to a request for comment. Previously Mr. Paxton said the Biden administration should focus on other priorities “instead of meddling in states’ sovereign rights.”