China and Russia's "profound" relationship will not change despite the turbulence in global geopolitics, Chinese President Xi Jinping told his counterpart Vladimir Putin at the opening of the BRICS summit in Kazan on Tuesday.

Xi and Putin in May pledged a "new era" of partnership between the two most powerful rivals of the United States, which they cast as an aggressive Cold War hegemon sowing chaos across the world.

President Vladimir Putin welcomed his Chinese counterpart, Xi Jinping, to Russia on Tuesday, as the Kremlin head prepares to host several leaders of developing nations at an intergovernmental summit this week.