Russia has warned that a military attack on Iran risks triggering a "chain reaction" that would destabilises the whole world.
Foreign minister Sergey Lavrov said Moscow was "seriously worried" about the prospect of military action against Iran and was doing all it could to prevent it.
He said: "The consequences will be extremely grave. It's not going to be an easy walk. It will trigger a chain reaction and I don't know where it will stop."
Mr Lavrov - a former ambassador to the United Nations - predicted a wave of refugees fleeing Iran, first into Azerbaijan and then on to Russia.
"But that is just one and not the main part of the problem... It's impossible to predict all the consequences," he said.
Mr Lavrov voiced concerns that an attack would exacerbate Muslim sectarian conflict in the Middle East - shown to have deadly consequences following the US and UK-led invasion in neighbouring Iraq. Read More