JACKSON — The office of Mississippi’s Democratic attorney general filed papers this week defending a law that bans most abortions after a fetal heartbeat is detected, as early as six weeks into pregnancy.

It’s one of the strictest abortion laws in the nation. Republican Gov. Phil Bryant signed it last month and it is set to take effect July 1.

The office of Attorney General Jim Hood argues the state has an interest in preserving fetal life “that exists from the moment of conception.”

The attorney general’s office also wrote: “As opposed to a vague and constantly shifting concept of ‘viability,’ detection of a fetal heartbeat is an objective milestone, and also an extremely accurate indicator of the likelihood a fetus will survive until birth.”

The Center for Reproductive Rights and Mississippi’s only abortion clinic are asking U.S. District Judge Carlton Reeves to block the Mississippi law before it takes effect.

In 2018, Mississippi enacted a law to ban abortions after 15 weeks, and Reeves struck it down, writing that it “unequivocally” violates women’s constitutional rights.

Abortion opponents are pushing for new restrictions in several states this year. They are emboldened by new conservative justices on the Supreme Court and are hoping federal courts will uphold laws that prohibit abortions before a fetus is viable outside the womb, the dividing line the high court set in its 1973 Roe v. Wade ruling that legalized abortion nationwide.

Attorneys for the Mississippi clinic and the Center for Reproductive Rights said in court papers March 28 that the new law is “the state’s second effort in only a year to adopt an unconstitutional ban on abortion well before viability.”

The attorney general’s office wrote that the new law does not ban all abortions but limits when they would be legal: “As such, it is akin to laws regulating the time, place, or manner of speech, which have been upheld as constitutional.”

The new Mississippi law says a physician who performs an abortion after a fetal heartbeat is detected could face revocation of his or her state medical license. It also says abortions could be allowed after a fetal heartbeat is found if a pregnancy endangers a woman’s life or one of her major bodily functions. Legislators rejected efforts to allow exceptions for pregnancies caused by rape or incest.

Reeves is scheduled to hear arguments May 21 over the clinic’s request that he block the law from taking effect.

Hood’s office also defended the 15-week abortion ban last year. He is running for governor, and this is his final year as attorney general.

Kentucky’s law banning abortion after the detection of a heartbeat was immediately challenged by the American Civil Liberties Union when Republican Gov. Matt Bevin signed it March 14, and a federal judge temporarily blocked it.

A federal judge also blocked another Kentucky law that would ban abortion for women seeking to end their pregnancies because of the gender, race or disability of the fetus.