Deputy Foreign Minister Sergei Kislyak, a career diplomat, was in charge of sensitive negotiations over Iran's nuclear programme, as well as international disarmament issues and relations with the US in his ministerial role.

He previously served as Russia's ambassador to the NATO military alliance.

Moscow's previous ambassador to Washington, Yury Ushakov, left his post last month to join Prime Minister Vladimir Putin's cabinet. The move was seen as giving Putin a continued major role in shaping Russia's foreign policy.