An effort to repeal Houston's recently approved gay-inclusive non-discrimination ordinance fell short of the number of verified signatures needed to put the law on the ballot in November.

The Houston Equal Rights Ordinance (HERO) prohibits discrimination in the workplace, housing and public accommodations on the basis of several factors, including sexual orientation and gender identity.

Mayor Annise Parker and City Attorney David Feldman announced that opponents had not collected the 17,269 signatures from registered city of Houston voters needed to get the issue on the ballot.

“With respect to the referendum petition filed to repeal the HERO ordinance, there are simply too many documents with irregularities and problems to overlook,” Feldman said. “The petition is simply invalid. There is no other conclusion.”

Opponents delivered their petition on July 3, claiming to have collected 50,000 signatures.

Pastor Dave Welch, who helped organize the repeal effort, vowed to sue the city and the mayor.

“We were well aware we were dealing with an administration that's willing to bend the rules,” Welch is quoted as saying by the Houston Chronicle. “Courts typically uphold the rights of the voters. We feel very confident in how that will go. Frankly, there was no respect for the rights of the voters in this process.”

Prior to passage in May, Houston was the largest U.S. city without such a law.