A federal judge on Thursday blocked Texas from enforcing voter ID requirements just weeks ahead of the November elections, knocking down a law that the U.S. Justice Department condemned in court as the state's latest means of suppressing minority turnout.

The ruling by U.S. District Judge Nelva Gonzales Ramos of Corpus Christi is a defeat for Republican-backed photo ID measures that have swept across the U.S. in recent years and mostly been upheld in court. However, the U.S. Supreme Court on Thursday night blocked Wisconsin from implementing a law requiring voters to present photo IDs.

Gonzales Ramos, an appointee of President Barack Obama, never signaled during a two-week trial in September that she intended to rule on the Texas law -- rebuked as the toughest of its kind in the U.S. -- before Election Day. But the timing could spare an estimated 13.6 million registered Texas voters from needing one of seven kinds of photos identification to cast a ballot.

The Justice Department says more than 600,000 of those voters, mostly blacks and Hispanics, currently lack any eligible ID to vote.

The Texas attorney general is seeking an emergency stay.