TRIPOLI, April 17 (RIA Novosti) - Gazprom [RTS: GAZP] announced it will close a deal to buy a controlling stake in Serbia's oil company Naftna Industrija Srbije (NIS) after the May 10 parliamentary election in the Balkan state.

Gazprom Neft, the main oil-producing arm of Gazprom, signed a deal on the purchase of a 51% stake in Serbia's state-owned oil monopoly during talks between Russian President Vladimir Putin and his Serbian counterpart Boris Tadic in Moscow on January 25.

"The agreement must be ratified. This is just a technical issue," Alexei Miller told reporters in Libya's capital, where he is staying as part of the Russian business delegation during Putin's visit to the North African country.

Gazprom reportedly offered $580 million for a 51% stake in NIS, which produces about a million metric tons (7.3 million barrels) of crude annually, refines 7 million metric tons (51 million barrels) and has Serbia's largest network of filling stations.