CARACAS, Venezuela (AFP) – Courts on Thursday ruled against the Venezuelan opposition’s efforts to remove the crisis-stricken country’s president, officials said, in a move that could block their recall referendum drive for good.

It was the latest blow for the center right-dominated opposition, whose aim of forcing a referendum this year through a series of preliminary petitions now looks practically impossible.

Socialist President Nicolas Maduro has vowed to hold on to power in the South American oil exporter, where an economic crisis has prompted food shortages and looting.

The pro-Maduro governors of the states of Aragua, Carabobo and Bolivar announced online that local judges had annulled the results of the last petition, held in June, in their states because of alleged fraud.

The opposition says Maduro and his allies control the courts and electoral authorities and are using them to cling to power.

Maduro’s opponents were hoping to mount a fresh petition next week, the last stage necessary for calling a referendum.

It remained unclear whether the rulings, if officially confirmed, would definitively derail the referendum drive by annulling a key stage in the process.

But the chances of Maduro being removed by referendum this year already looked impossibly slim. The electoral authorities have said a referendum could not take place before mid-January.

Under constitutional rules, if voters do not remove Maduro from office by January 10, his hand-picked vice president will finish his term, which ends in 2019.