The Russian foreign ministry on Sunday condemned the unilateral declaration by the United States that UN sanctions on Iran are back in force as "illegitimate" and "unacceptable".
"The illegitimate initiatives and actions of the United States by definition cannot have international legal consequences for other countries," the foreign ministry said in a statement.
Russia, a key ally of Iran, accused Washington of putting on a "theatrical performance" and insisted that the US statements "do not correspond to reality."
It accused the US of "trying to force everyone to wear virtual reality goggles" and accept its version of events, adding: "The world is not an American computer game."
Washington's defiance has dealt a "serious blow to the authority of the UN Security Council" and showed "open contempt for its decisions and for international law as a whole," the ministry said.
"This is unacceptable, and not only for us, but for other members of the Security Council too."
Russia said it "fully supports" the position of the majority of Security Council members that the US moves are "legally and procedurally null and void."
Russia said that efforts to ensure the fulfilment of the 2015 nuclear accord would be continued.
"The US should not exacerbate the situation but immediately renounce its course to destroy the JCPOA (2015 nuclear deal)," Moscow said.