Russia's foreign ministry on Thursday warned the United States not to take military action against Iran, amid speculation over whether Washington will enter the war alongside Israel.

Moscow issued its warning after Russian President Vladimir Putin and his Chinese counterpart Xi Jinping in a phone call condemned Israeli attacks on Iran and urged a diplomatic solution to the conflict.

Russian foreign ministry's spokeswoman Maria Zakharova told reporters: "We would like to particularly warn Washington against military intervention in the situation."

Any US military action "would be an extremely dangerous step with truly unpredictable negative consequences", she added.