John McCain is calling on Russia to cease military action in Georgia and withdraw its forces.

Campaigning in Iowa, the Republican presidential hopeful called for the U.S. to convene an emergency session of the U.N. Security Council to resolve the crisis.

Georgian troops launched a major military offensive earlier Friday to regain control of the breakaway republic of South Ossetia, prompting a furious response from Russia.

McCain told reporters: "What's most critical now is to avoid further confrontation between Russian and Georgian military forces."

He said the U.S. should work with the European Union to put diplomatic pressure on Russia and help establish an independent peace keeping force in South Ossetia.