MOSCOW, February 26 (RIA Novosti) - The board of directors of Gazprom approved the purchase of 50% of Rosukrenergo AG stock from Gazprom's subsidiary Gazprombank, Russia's energy giant said in a statement Sunday.

The deal was aimed at optimizing the management of Gazprom's main assets, the statement said.

Rosukrenergo AG was set up in July 2004 and registered in Switzerland. Subsidiaries of Gazprom and Raiffeisen Investment AG are the company's shareholders. Rosukrenergo is the sole natural gas importer to Ukraine.

Rosukrenergo was chosen to form a joint venture with Ukrainian national energy company Naftogaz under a January 4 deal that ended a bitter dispute over gas prices between Russia and Ukraine.

"Taking into account that Gazprombank participated in establishing Rosukrenergo AG and in its operations, and it actually acted on behalf of Gazprom, the price equal to Gazprombank's historic expenditures [a total of investment and expenditures on interest, exchange-rate and administrative payments] was acknowledged as the fair cost of the package being purchased," the statement said.

The Gazprombank board of directors preliminarily approved the deal on January 16.