Image copyright AP Image caption Abortion rights supporters protest against the law outside the Texas governor's mansion

A US judge has struck down part of a Texas abortion law that would have closed more than a dozen clinics.

Judge Lee Yeakel said key provisions were unconstitutional because they in effect blocked access to abortion.

The legislation includes the requirement for clinics to meet the same surgical standards as hospitals.

The issue has become a battleground in November's election for state governor, with supporters and opponents of the law vying for the post.

The election pits Texas Attorney General Greg Abbott against one of the law's fiercest critics, State Senator Wendy Davis.

A previous legal battle ended with an appeals court upholding another provision of the law.

A spokeswoman for Mr Abbott said his office would immediately appeal against the latest decision to the US 5th Circuit Court for Appeals in New Orleans, the same court that upheld a provision requiring doctors performing abortions to have admitting privileges at a nearby hospital.

The law also limits the use of abortion-inducing drugs, bans abortions at the 20th week of pregnancy and requires clinics to meet surgical facility standards

Judge Yeakel's decision struck down provisions that required surgical facilities for any type of abortion, including medication-induced, as well as admitting privileges for two specific clinics.

Image copyright AP Image caption Anti-abortion groups and abortion rights groups held separate rallies outside the courthouse

They were due to take effect on Monday.

State lawyers argued the provisions were for safety reasons and women would not suffer from fewer abortion clinics, saying nearly nine in 10 women would still live within 150 miles (241km) of a provider.

Lt Governor David Dewhurst told the Texas Tribune the court's decision "undermines a concerted effort to improve health care for women in Texas".

Judge Yeakel rejected both arguments, finding that surgical facilities made little difference to the already low risk to women, and that the law would in effect leave open at most eight clinics to serve the entire state.

Media playback is unsupported on your device Media caption Inside Mississippi's last abortion clinic

He added that women seeking abortions in the most western and southern parts of the state, where poverty and distances to major metropolitan areas were greater, would see the most obstacles.

"A woman with means, the freedom and ability to travel and the desire to obtain an abortion will always be able to obtain one, in Texas or elsewhere," he wrote.

"However, Roe's [The Supreme Court's 1973 ruling on abortion] essential holding guarantees to all women, not just those of mean, the right to a pre-viability abortion."

Senator Davis, who launched her campaign for governor after a nearly 13-hour long filibuster against the bill, called the ruling a "victory for women's health care" in a tweet.