(Reuters) - A U.S. federal judge blocked on Friday an order from Republican Texas Governor Greg Abbott limiting the number of drop-off sites allowed for absentee ballots statewide to just one per county, a constraint Democrats denounced as blatant voter suppression.

Abbott’s Oct. 1 absentee voter proclamation, which he said was aimed at preventing election fraud, required the closure of more than a dozen satellite drop-off box locations in at least two counties.

But U.S. District Judge Robert Pitman, siding with voting rights advocates who challenged Abbott’s move, found it would create voter confusion and force absentee voters wishing to deliver their mail ballots in person to travel farther, wait in longer lines and risk greater exposure to the coronavirus.

“These burdens fall disproportionately on voters who are elderly, disabled, or live in larger counties,” Pitman, who sits in Austin, the state capital, wrote in his 46-page decision.

There was no immediate reaction from the governor to the decision, which could be appealed to the 5th U.S. Circuit Court of Appeals.

Abbott’s order was imposed after absentee voting in the state had begun for the Nov. 3 U.S. presidential election, with multiple absentee-ballot collection centers advertised in some counties for weeks.

Drop-off sites were set up to allow absentee voters to personally submit ballots in advance, rather than depend on the U.S. Postal Service to deliver them by mail on time, while also avoiding potentially crowded polling places on Election Day.

TEXAS RACE COULD BE CLOSE

Texas is a longtime Republican stronghold, but this year Republican President Donald Trump and his Democratic challenger, Joe Biden, are waging what could be a tight race to win the state’s 38 electoral votes.

Texas is one of the few U.S. states that limit who can request absentee ballots - only voters who are over the age of 65, have a disability, are confined to jail or will be out of town on Election Day can vote by mail.

Earlier this year, the state Supreme Court and a federal appeals court rejected efforts to extend mail voting to all Texans amid the COVID-19 pandemic.

In light of the pandemic, Abbott in July authorized voters who were already permitted to vote by mail to submit their ballots in advance, and extended early voting by several days.

His latest order, however, changed the rules again just a month before Election Day and would have been especially burdensome for absentee voters in places like Harris County, a sprawling Democratic stronghold that includes the city of Houston.

“To force hundreds of thousands of seniors and voters with disabilities to use a single drop-off location in a county that stretches over nearly 2,000 square miles is prejudicial and dangerous,” Harris County clerk Chris Hollins said, referring to an area equivalent to 5,200 sq. km.

The fight between Republicans and Democrats over absentee ballots has become a defining issue of the 2020 election, with voting by mail expected to surge due to the pandemic. Without citing evidence, Trump and his Republican allies have warned that absentee voting is rife with fraud.

In ordering the number of ballot-return centers restricted to one per county, Abbott said the move would “ensure greater transparency and will help stop attempts at illegal voting.”

Judge Pitman dismissed Abbott’s rationale as “a pretext,” noting that the state had argued that satellite dropoff centers should be banned during early voting while authorizing their use on Election Day “without regard to ballot security concerns.”