A federal appeals court has upheld key provisions of Texas' strict anti-abortion law that could result in only seven clinics providing abortion services to women in the nation's second biggest state with a population of 26.9 million.

The 5th US Circuit Court of Appeals made the ruling in a lawsuit challenging some of the toughest abortion restrictions in the US, including requirements that all abortion-providing health clinics employ hospital-level operating standards.

Operators of small abortion clinics say they could not comply with the requirements since upgrading their facilities would cost them millions of dollars which they could not afford. These clinics and other abortion-rights supporters contend that the law was only meant to deny abortion services to women.

However, Republican Gov. Greg Abbott and other conservatives who support the law say the high standards stipulated in the law were only meant to protect women's health.

The New Orleans-based appeals court, which is considered one of the most conservative courts in the US, allowed Texas to enforce the restrictions when abortion service providers first filed a lawsuit in 2013. But the US Supreme Court temporarily shelved the law last year.

Many abortion clinics in Texas have shut down as a result of the law. From the 40 clinics that were operating in 2012, the number is now down to 17. That sharp decline began after the 5th Circuit upheld another part of the 2013 law that required doctors to have admitting privileges at nearby hospitals.

The Texas Hospital Association said the admitting privilege requirement is unnecessary as women experiencing abortion complications can got to an emergency room for treatment and do not need their abortion doctor hospital staff for this to happen.

With the new restrictions, the only remaining abortion clinics in Texas would be those situated in major cities.

Attorneys for Texas rejected the arguments presented by critics who said fewer abortion facilities would pose a burden to women in the state needing such service. The lawyers said nearly nine in 10 women in Texas would still live within 150 miles of an abortion service provider despite the restrictions imposed by the law.

Texas Attorney General Ken Paxton lauded the ruling, saying that "HB 2 both protects the unborn and ensures Texas women are not subjected to unsafe and unhealthy conditions."

"Today's decision by the Fifth Circuit validates that the people of Texas have authority to establish safe, common-sense standards of care necessary to ensure the health of women. Abortion practitioners should have no right to operate their businesses from sub-standard facilities and with doctors who lack admitting privileges at a hospital. This ruling will help protect the health and well-being of Texas women," he said.

The Center for Reproductive Rights and the Texas women's health care providers said they will appeal the ruling to the US Supreme Court.

"Not since before Roe v. Wade has a law or court decision had the potential to devastate access to reproductive health care on such a sweeping scale. Once again, women across the state of Texas face elimination of safe and legal options for ending a pregnancy, and the denial of their constitutional rights," said Nancy Northup, president and CEO of the Center for Reproductive Rights.