NEW YORK ( TheStreet) -- Russia has responded to U.S. and European sanctions by signing a long-term deal to supply China with natural gas.
Russia and China signed the deal on Wednesday, providing the world's top energy user a major new source of the clean-burning fuel.
Russia will supply 38 billion cubic meters of gas to China each year for 30 years under a contract valued in excess of $400 billion overall, Reuters reported.
The gas will be transported along a new pipeline linking Siberian gas fields to China's main consumption centers near its coastline.
Russian President Vladimir Putin and Chinese leader Xi Jinping oversaw the signing in Shanghai between Russian state-controlled company Gazprom (OGZPY) and China National Petroleum Corp.
"This is the biggest contract in the history of the gas sector of the former USSR," Putin said. "Our Chinese friends are difficult, hard negotiators," he added, mentioning that talks lasted until 4 a.m.
The deal is a victory for Putin, who has dealt with sanctions imposed on Russia since the country annexed Crimea.
The new partnership is pivotal for Russia as customers in Europe attempt to reduce their reliance on Russian gas.
Alexei Pushkov -- a Putin loyalist and senior member of parliament, who is included on a U.S. list of sanctions -- said the gas deal showed Russia can't be isolated.
"Gas contract with China for 30 years has a strategic importance. Barack Obama should abandon the policy of isolating Russia: it will not work," Pushkov said on Twitter (TWTR).
Russia has remained steadfast in its dealings with Ukraine since sanctions were imposed by Western countries. Although outside investors have fled the country, pushing the country's equity market lower, Russia has remained undeterred in its behavior.