The move to suspend Russia's membership in the G8 is the latest direct response from major countries allied against Russia's annexation of Crimea.

"International law prohibits the acquisition of part or all of another state's territory through coercion or force," the statement said. "To do so violates the principles upon which the international system is built. We condemn the illegal referendum held in Crimea in violation of Ukraine's constitution.

"We also strongly condemn Russia's illegal attempt to annex Crimea in contravention of international law and specific international obligations."

Russian Foreign Minister Sergey Lavrov said earlier in the day that being kicked out of G8 would be no big deal.

"G8 is an informal organization that does not give out any membership cards and, by its definition, cannot remove anyone," he said during a news conference. "All the economic and financial questions are decided in G20, and G8 has the purpose of existence as the forum of dialogue between the leading Western countries and Russia."

Lavrov added that Russia was "not attached to this format and we don't see a great misfortune if it will not gather. Maybe, for a year or two, it will be an experiment for us to see how we live without it."

In a nod to political and economic reforms, the United States, Britain, Canada, France, Germany, Japan, and Italy added Russia to their group in 1998 -- transforming it from the G7 to the G8.

The United States and its allies in Europe are "united in imposing a cost on Russia for its actions so far," Obama said earlier in the Netherlands where he attended a nuclear security summit with other world leaders.

Western powers have imposed sanctions and other penalties against specific people in Russia close to President Vladimir Putin.

BA/BA