By Daniel Bases
CARACAS (Reuters) - Venezuela's Supreme Court blocked high-profile opposition challenger Leopoldo Lopez on Monday from running against President Hugo Chavez in a 2012 vote despite an international ruling in his favor.
The decision narrows the field of aspirants to take on Chavez in the October 7, 2012, election. It will draw the ire of human rights groups who say the socialist leader has stamped on freedoms in the South American nation of 29 million people.
Lopez, a 40-year-old U.S.-educated politician, was one of three leading opposition candidates vying to win the opposition coalition's presidential primary in February.
But the Supreme Court chose to ignore a ruling by the Costa Rica-based Inter-American Court of Human Rights last month that said Lopez's disqualification from politics over corruption allegations was unjustified.
"This Supreme Court ... declares that the Inter-American Court of Human Rights decision against the Venezuelan state cannot be executed," the court said in a statement, specifying that Lopez can run in elections but not take up any office.
The charismatic and baby-faced Lopez made his name as mayor of the wealthy Chacao district in Caracas. He was favored to win the race for mayor of the whole city in 2008, but he and scores of other politicians -- most from the opposition -- were blocked by Chavez's comptroller general.
Accused but not tried for corruption, Lopez was barred from seeking public office until 2014.
One accusation stems from a donation state oil firm PDVSA made in 1998 to a political organization of which he was a member. The donation was controversial because his mother, a PDVSA employee at the time, signed the check.
Authorities also accused Lopez -- but never tried him -- of illegal diversion of Chacao district funds under his control.
Lopez, the son of a well-to-do family, says the accusations were trumped up and called it unconstitutional to suspend him from politics without first giving him a trial.
The human rights court is part of the Organization of American States (OAS), of which Venezuela is a member, and its decisions are supposed to be binding.
Chavez, who habitually accuses the OAS of being beholden to U.S. interests, dismissed the court's decision on Lopez at the time as "worthless.
The 57-year-old president, who has taken a tough line on plenty of his political opponents during a nearly 13-year rule, flew to Cuba at the weekend for checks after cancer treatment.
There was no immediate reaction from Lopez to Monday's ruling, with speculation now on whether he will fight the decision or lend his support to another candidate.
(Additional reporting by Marianna Parraga and Eyanir Chinea; Editing by Andrew Cawthorne and Eric Beech)