The Guardian reports: Iran is due to open talks with UN nuclear inspectors on Sunday in an attempt to allay their suspicions of a covert Iranian weapons programme, the first such discussions in more than three years.

The three days of meetings in Tehran between Iranian nuclear officials and a team from the International Atomic Energy Agency (IAEA) represent the only diplomatic progress in more than a year, as tensions mount over Iran’s nuclear programme and western attempts to cut off the country’s oil trade.

Diplomats familiar with the visit said that the IAEA team would seek assurances that they will be able to interview key Iranian scientists suspected of past involvement in weapons research, visit sensitive sites and see documents concerning the procurement of dual-use technology. The Iranian government denies it is seeking to make nuclear weapons, insisting its research is for scientific or civil power-generating purposes.

Diplomats and analysts have played down prospects of a quick breakthrough.

If the talks were to collapse, the pressure on Iran could intensify. The IAEA has warned that Tehran could be referred to the UN security council for possible further punitive measures if it fails to cooperate.