KIEV, Sept. 7 - A Ukrainian court revoked privatization of an 18.3% stake in the country's largest oil refinery, UkrTatNafta, and ruled the stake must be returned to the government, the State Property Fund said Wednesday.

The stake, owned by two offshore companies, is believed to have been in fact controlled by the Russian oil company Tatneft, which jointly with the government of Russia's republic of Tatarstan had controlled the majority interest in the refinery.