Moscow - Serbian President Boris Tadic flew to Moscow on Wednesday to ink a multimillion-dollar energy deal with his Russian counterpart Dmitry Medvedev.

Under the deal, Serbia will sell a controlling stake in its oil monopoly NIS to Russian state giant Gazprom in exchange for a share in a strategic Russian pipeline through Serbia.

Serbian media reported the 51-per-cent stake was sold for 400 million euros (560 million dollars).

Gazprom will also invest a further 550 million euros in the modernization of NIS's refineries and the construction of a gas storage facility in northern Serbia, media said.

Routing of the 13-billion-dollar South Stream pipeline through Serbia, carrying Russian gas under the Black Sea to Western Europe, would secure the country supplies and transit fees.

Russia, a long-time ally of Serbia, backed Belgrade's opposition to the breakaway province of Kosovo's unilateral declaration of independence.

But the sale of NIS caused a rift among Serbian lawmakers. Economy Minister Mladjan Dinkic protested, saying that the price was too low and that the Russians gave no guarantees that the South Stream gas line would go through Serbia. (dpa)