Reaching a long-term nuclear deal with Tehran will be “challenging,” according to EU foreign policy chief Catherine Ashton.
She has been meeting with Iranian President Hassan Rouhani and other leaders during her first visit to the Islamic Republic.
“Difficult, challenging, there’s no guarantee we’ll succeed,” said Ashton.
“But I think it’s very important, with the support of the people of Iran for the work that is going on by the minister and his team, and with the support of the international community for my work, that we should aim to try and succeed.”
Under an interim deal, Iran has curbed some of its nuclear activities in return for a limited easing of sanctions.
Further talks between Tehran and world powers take place in Vienna later this month.
A long-lasting nuclear deal with Iran would help put an end to years of hostility between Tehran and the West.
Iran has repeatedly rejected allegations by Western countries that it is seeking a nuclear weapons capability. It says its nuclear work is for power generation and medical purposes.