PRAGUE (AP) -- A court in the Czech Republic blocked on Tuesday the government from signing a deal with South Korea's KHNP to build at least two nuclear reactors in country.

KHNP won a lucrative public tender last year, beating a competing bid by France's EDF.

The two new reactors will be built at the existing Dukovany power plant in an effort for the country to wean itself off fossil fuels.

The contract between the dominant power company CEZ, where the Czech state has a majority stake, and the South Korean company was scheduled for Wednesday.

EDF challenged the signing of the deal at the regional court in the second largest Czech city of Brno on Friday after the Czech anti-monopoly office dismissed its complaint about the tender.

The court said that the deal could not be signed before it rules on the EDF case, because then there would be no way to change it even if the French company won.

It is not clear when that might happen.

Prime Minister Petr Fiala said he believed the tender was "correct and in line with law." CEZ said the Korean bid was the better one, and the tender was transparent and fair. EDF had no immediate comment.

The two new reactors will complement Dukovany's four 510-megawatt units that were completed in the 1980s. The government estimated they would each cost about 200 billion koruna ($9.1 billion).

The first new reactor is expected to become operational for a trial by 2036, the second about two years later.