President Vladimir Putin said relations between Russia and China had developed to an all-time high and they would play a significant role on the global political stage.
However, he said that while Russia would widen co-operation with China, it was not seeking to form a military bloc with its neighbour.
"It will significantly influence the modern architecture of international relations," Putin said in a nationally televised phone-in, but added that they were "not considering the question of a military-political alliance".
Russia and China were "natural neighbours and therefore natural partners", Putin said. Still, a system of military blocs had "outlived itself", he said.
"Our relations with China are developing quite successfully and are at an unprecedentedly high level of trust and co-operation.
"China will be the world's No1 power eventually. That can be considered a hard fact."
The crisis in Ukraine has increased the importance of Russia's relationship with China, its largest trade partner outside the European Union and the only country in the United Nations Security Council not to censure its actions in Crimea. Putin is due to meet President Xi Jinping in Beijing next month to discuss issues including a 30-year gas supply deal.
Gazprom and CNPC signed a framework agreement in 2009 which could eventually see almost 70 billion cubic metres of Russian gas sent to China annually for the next 30 years.
The talks over the past decade have become mired in differences over pricing and the final contract has proved elusive. But analysts have said that China is likely to use Russia's growing isolation from Western markets to negotiate a lower price.
Xi met Russian Foreign Minister Sergey Lavrov in Beijing on Tuesday. They discussed Putin's visit next month.
Reuters, Bloomberg, Agence France-Presse