Washington: The US has said it was "deeply disappointed" at Iran`s failure to accommodate the UN nuclear watchdog over its controversial nuclear programme.
State Department spokeswoman Victoria Nuland criticised Iran for missing another chance to cooperate with the International Atomic Energy Agency (IAEA) by failing to agree on a structured approach and denying the agency access to its Parchin military site, Xinhua reported.
The Parchin military site is suspected by Western powers of being used for conducting nuclear bomb-related experiments.
"They (Iran) were, once again, unable to come to agreement with the IAEA either on a structured approach or on being able to visit Parchin," Nuland was quoted as saying.
"We`re obviously deeply disappointed that Iran has once again missed an opportunity to cooperate with the IAEA and to provide the international community with the transparency that we`re all seeking in order to resolve our concerns about Iran`s nuclear programme," she said.
Nuland said discussions with Iran were continuing to set a date and venue for fresh talks with the P5+1 comprising Britain, China, France, Russia, the US and Germany.
"You know that we`ve been seeking to address this issue on two tracks," the spokeswoman said.
"There`s the IAEA track, which is designed to give us all transparency about what`s exactly going on, and then the efforts of the P5+1 to try to get Iran to really roll back whatever may be going on on the military side."
Three rounds of talks were held in 2012 between Iran and the P5+1 but no breakthrough was made.
Washington has set a March deadline for Iran to begin "substantive cooperation" with the IAEA or face the UN Security Council.
Iran insisted Friday that progress was made in the latest two-day talks with the IAEA ending Thursday. The two sides agreed to meet again Feb 12.
The UN Security Council and Western powers have imposed sanctions on Iran over its refusal to stop uranium enrichment activities, while Tehran insists on the peaceful nature of the programme.