Russian President Dmitry Medvedev has said Iran is "moving closer" to having nuclear weapons capability. It is one of the first times that the Russian leadership publicly indicated that Tehran is working towards having a nuclear weapon. Russia has strong economic and military ties with Iran and has traditionally been an ally of Tehran. However, Moscow recently adopted a tougher stance, and backed the fourth round of UN sanctions that was imposed last month.

"Iran is moving closer to possessing the potential which in principle could be used for the creation of nuclear weapons," Medvedev told a meeting of ambassadors in Moscow. The US and major European Union powers suspect that Iran is trying to build nuclear weapons. Iran claims its nuclear program is peaceful.

On 10 June, the UN Security Council approved a fourth round of sanctions on Iran, including tighter financial curbs and an expanded arms embargo. Since then, the US and EU have unilaterally imposed additional sanctions, including a ban on investment in Iran's oil and gas industry, as well as trade with key banks and individuals.