US Secretary of State Hillary Clinton has urged Iran to commit to talks over its nuclear programme.
Clinton was responding to a letter in which Tehran expressed willingness to resume negotiations with the five permanent members of the UN Security Council, plus Germany.
“We have been reviewing Iran’s proposal to resume talks on its nuclear activities, and consulting closely between us and our other P5+1 partners,” Clinton told reporters in Washington.
“This response from the Iranian government is one we have been waiting for, and if we do proceed, it will have to be a sustained effort that can produce results.”
Talks on Tehran’s atomic ambitions collapsed over one year ago.
President Mahmoud Ahmadinejad took part in a ceremony in the Iranian capital on Wednesday to celebrate what the government called “significant advances” in nuclear power.
Western countries fear Iran will eventually try to build nuclear wewapons; Tehran insists the programme has purely peaceful aims.