ST. PETERSBURG, October 2 (RIA Novosti) - Russia's Gazprom and Germany's E.ON AG signed an asset swap agreement on Thursday involving northwest Siberia's Yuzhno-Russkoye oil and gas field.

Under the deal, signed in St. Petersburg in the presence of German Chancellor Angela Merkel and Russian President Dmitry Medvedev, E.ON, the world's largest utility, will receive 25% minus one share in Gazprom subsidiary Severneftegazprom, while the Russian energy giant will get a 49% stake in E.ON's ZAO Gerosgaz, which holds a 2.93% interest in Gazprom.

Severneftegazprom holds a license for the Yuzhno-Russkoye oil and gas deposit, which has recoverable reserves of 600 billion cubic meters of gas.

Gerosgaz, founded in 1999, is a joint stock company in which Gazprom Export holds a 51% interest, and E.ON Ruhrgas AG has 49%.

The transfer would reduce E.ON's stake in Gazprom to 3.5% from 6.43%. The asset swap is to be completed in the second half of 2009.

Gazprom CEO Alexei Miller said the deal shows that the companies are strategic, long-term partners.

"We are pleased to welcome E.ON into the Yuzhno-Russkoye project; it will become a third partner and will be able to engage in gas production in Russia," he said.