Iran: US and EU 'cautiously optimistic' on new talks
The United States and the European Union have expressed cautious optimism over Iran's willingness to return to talks on its nuclear programme.
Speaking in Washington, US Secretary of State Hillary Clinton said a letter from Iran to the US and its allies was "one we have been waiting for".
EU foreign policy chief Catherine Ashton said she was "cautious" but "optimistic" that talks could resume.
Both said, however, said that they were still studying the reply.
Talks between Iran and six world powers - the US, UK, France, Germany, Russia and China - on Tehran's nuclear programme collapsed a year ago.
Iran has in the past insisted on including a broad range of topics on the agenda.
Ms Clinton said it appeared that Tehran now accepted that talks would focus on the nuclear issue.
The US and Western powers suspect Iran is seeking to develop nuclear weapons, but Iranian authorities insist the nuclear programme is peaceful.
In recent months, Western countries have stepped up pressure on Iran over the nuclear issue, with the EU and US both introducing wide-ranging sanctions on the country.