The Texas attorney general has said he will challenge abortion clinics' appeal asking the U.S. Supreme Court to consider striking down safety regulations that only about a dozen of the state's abortion clinics can meet.

Texas attorney general Ken Paxton's office stated Sept. 2 that the 2013 law aims to "protect the health and safety of women and ensure abortion clinics in Texas meet basic standards."

Paxton's office said he plans to file a response to abortion groups' request for a hearing.

The 2013 Texas law increased safety regulations for abortion clinics and physicians who perform abortions. It requires all abortion clinics in the state to follow surgical facility standards in their buildings, equipment, and staffing. Physicians at the clinics must have admitting privileges at a hospital within 30 miles, and a 24-hour hotline for patients experiencing post-abortive complications.

Most of these rules would have gone into effect July 1. By a 5-4 margin on June 29, the U.S. Supreme Court blocked the law pending further action from the plaintiffs.

About half of Texas' 41 abortion clinics have already closed due to the law. The abortion clinics' Wednesday appeal to the Supreme Court said that about half of the remaining clinics could close if the law is not halted.

The abortion clinics noted that Texas is the second-most populous state in the U.S. and has more than 5.4 million women of reproductive age, the New York Times reports.

The abortion providers said the law would "delay or prevent thousands of women from obtaining abortion." They said this would mean some women would then turn to "unsafe or illegal methods" of abortion.

Some abortion clinics cannot afford upgrades to meet the safety standards, while some are not in range of a hospital that will accept an abortionist.

A federal appellate court has already allowed an exemption for one doctor who performs abortions in McAllen, the center of a metropolitan area more than 800,000 which is 60 miles away from Brownsville. The court said that in the McAllen doctor's case, the requirement of hospital admitting privileges would create an unconstitutional burden on women seeking abortions there.

Paxton has previously spoken in defense of the law.

"Abortion practitioners should have no right to operate their businesses from sub-standard facilities and with doctors who lack admitting privileges at a hospital," he said in June when a federal appellate court upheld the law.

Texas Right to Life has also supported the law.

Emily Horne, senior legislative associate with the Texas pro-life group, said June 9 that the law means "Texas women and their preborn children will no longer be subjected to the grotesque reality inside Texas abortion facilities."

Some backers of the law cited the case of Philadelphia abortionist Kermit Gosnell, who in 2013 was convicted of three counts of first-degree murder and one count of involuntary manslaughter as a result of negligent practices. The grand jury report in the case said that surgical facility standards for Gosnell's clinic, like wider hallways for paramedic access, could have saved the life of one young woman who died.

The Texas law also bans abortions after 20 weeks, on the ground that an unborn baby at that age can feel pain. This provision has not faced legal challenge.