The European Union called Wednesday on Iran to sign an accord with the International Atomic Energy Agency that would enable the UN watchdog to verify the nature of its controversial nuclear activities. IAEA chief Yukiya Amano said after visiting Iran in May that Tehran would soon sign a deal to allow greater access to sites, documents and people involved in its nuclear programme -- but no such agreement has yet emerged. \"We call on Iran to conclude the agreement without further delay,\" the EU said in a statement to the meeting of the IAEA board of governors being held in Vienna this week. \"The EU has once again to stress the importance of granting early access to all sites, persons and information as and when requested by the agency,\" the statement said, making particular reference to a military base at Parchin. The IAEA, which is holding a new round of talks with Iran in Vienna on Friday, has been seeking access to the Parchin base near Tehran, where it believes suspicious explosives testing has been carried out. Iran has denied the IAEA demands, insisting the site is of no significance to its nuclear programme. The EU also said that despite the increased dialogue between Iran and the nuclear watchdog, it remained deeply concerned that there had been \"no substantive delivery\" on the requirements of an IAEA resolution in November calling for greater cooperation by Tehran. On Tuesday, US envoy to the IAEA Robert Woods said he was \"not optimistic\" of an accord on Iran\'s nuclear activities, which the West and Israel suspect is aimed a building the bomb, charges denied by Tehran.