The US rejects the idea of any nation claiming a sphere of influence, Vice President Joe Biden told a Washington think tank, arguing that the crisis in Ukraine was about the principles and values of the West and international order.

"We will not recognize any nation having a sphere of influence," the vice president said during a speech at the Brookings Institution on Wednesday. It remained unclear whether the remark applied to US influence around the globe, or referred only to Russia, China and other countries.

RAW: Reporters hammer State Dept. spox over Ukraine, Biden's 'spheres of influence' comment: