BBC News with Marion Marshall

The United Nations nuclear watchdog, the IAEA, has expressed deep and increasing concern about Iran's nuclear programme. A resolution passed by the agency's board called on Tehran to clear up outstanding questions about its nuclear capabilities without delay, but stopped short of referring Iran to the UN Security Council. Last week, an IAEA report said there was considerable evidence that Iran had undertaken the experiments geared towards developing a nuclear weapons capability. James Reynolds reports.

The IAEA board has voted to express its deep concern about Iran. It's asked the IAEA director general to report back in March, but it's not referring the country to the United Nations for further sanctions - in other words, criticism but no immediate action. The four Western countries would have preferred moves towards more sanctions, but Russia and China said no. Western diplomats are happy that the six countries have agreed a single response to Iran. But it's not yet clear what kind of impact a statement of criticism will have on the government of the Islamic republic.