UN nuclear watchdog chief Mohamed ElBaradei said Friday that there was no sign of nuclear activity at a suspect site in Iran, the Parchin military testing ground near Tehran.
US officials had pressed the International Atomic Energy Agency (IAEA) to investigate the Parchin site but ElBaradei said: "We do not have any indication that this site has any nuclear-related activities."
"We are aware of this new site," he however told a press conference at an IAEA board of governors meeting.
Iran denied Thursday that it had carried out any nuclear-related activity at Parchin, a huge military complex 30 kilometres (19 miles) south-east of Tehran.
A senior US official told AFP the United States was concerned about high-explosives testing in Parchin that may "amount to (nuclear) weapons intent".
Iranian official Hossein Mousavian said in Vienna that the IAEA had not asked to visit Parchin as part of its investigation of Iran's nuclear program.
He said that "if this is requested by the IAEA, we are fully ready to co-operate."
Mousavian said the IAEA had asked Iran "four weeks ago about reports from open sources of explosive testing but they did not mention Parchin."
Diplomats have told AFP, however, that the IAEA had asked to visit Parchin and that the Iranians have not agreed to the visit.
Parchin is a site for a variety of defence projects, including Defence Industries Organisation (DIO) work in chemical explosives.
Iran maintains that its nuclear program is strictly civilian and peaceful and that it is not developing atomic weapons.
A diplomat close to the IAEA confirmed that the agency had asked to send inspectors to Parchin but said this was not included in an IAEA report on Iran published September 1 since "whenever you are in the negotiating process, you should not mention what you are negotiating.
ElBaradei defended himself against charges of hiding information on Parchin.
He said the report contained "all the facts that we think should be brought to the attention of the (IAEA) board (of governors) at this stage.
"The report is comprehensive," he said.