Russia will remain a key oil and natural gas supplier through its strong connections to the European market, the chairman of Germany's BASF said.

"Our cooperation makes outstanding contribution towards securing energy supplies to Europe," BASF Chairman Kurt Bock said in a statement.

BASF subsidiary Wintershall is a partner to Russian energy company Gazprom in the Nord Stream natural gas pipeline running through the Baltic Sea to the German coast and sending Russian natural gas into the European market.

Gazprom in early September signed a shareholder agreement on the development of the second phase of the twin Nord Stream pipeline system in the Baltic Sea with German energy companies BASF and E.ON, French company ENGIE, Austria's OMV and Royal Dutch Shell.

Under the proposed expansion, two more lines would be added to the existing network running to the German coast, bringing the net aggregate annual capacity to 1.9 trillion cubic feet of natural gas.

European leaders are wary of Gazprom's dominance in the regional energy sector, calling on members of the European Union to get their reserves from at least two different sources. Gazprom has faced anti-trust issues as well because it controls both the reserves and the transit arteries that carry them.

"Our cooperation with BASF/Wintershall may serve as an example of trust between the companies, example of strategic vision of the business development and a striking illustration of significant contribution to the EU energy security," Gazprom Chairman Alexei Miller said.

Russia's economy, meanwhile, depends heavily on oil and natural gas for revenue. The International Monetary Fund expects Russia to linger in recession, with the economy on pace to contract by up to 4 percent. In September, Russian President Vladimir Putin called for financial stability and pushed for efforts "to considerably decrease the federal budget's dependence on oil prices."

Bock, however, said cooperation with Russia was more than just a long-term business opportunity for the German company.

"I am confident that Russia is and will remain a major and reliable supplier of oil, natural gas and other energy sources to Europe, and Europe is and will remain an important and stable sales market for Russia," he said.