KIEV, Sept. 13 – The unification of the Russian gas giant Gazprom and Ukraine's national gas company Naftogaz Ukrayiny into a joint venture may cause Russia to change its position on the construction of the South Stream gas pipeline, Deputy Chairman of the Russian State Duma, President of the Russian Gas Society Valery Yazev has said.

"But we cannot sit here and wait until Ukraine decides whether it will set up a joint venture. Because, there are time constraints, there are agreements on the construction of the South Stream and we cannot violate all of these agreements, which involve a number of European states and their economic entities. That is why Ukraine needs to make up its mind as soon as possible," he said during a video linkup between Kiev and Moscow on Monday.