WASHINGTON, June 24 (RIA Novosti) - Russia could call time on natural gas supplies to Europe in 10-15 years in favor of sales to China and India, a prominent U.S. scholar said.

Marshal Goldman, an expert on Russia and the author of the recently published book, "Petrostate: Putin, Power and the New Russia," said the switch was likely because China and India - with their growing economies hungry for energy - were very interested in Russian natural gas supplies. The only question was whether Russia would be able to deliver the gas.

According to Goldman, China already purchases large quantities of petrol from Russia. "Every day, up to ten freight trains loaded with Russian petrol leave for China," he said in an interview with RIA Novosti.

In the book, Goldman said Russia has become a powerful state that can use energy supplies to exert pressure on its European partners.

"Russia has become a strong state," Goldman told RIA Novosti, adding that he would like to discuss this issue at a meeting with Russian leaders within the framework of the Valdai International Discussion Club.