Nuclear talks between Iran and the International Atomic Energy Agency broke down again Friday after the nuclear watchdog’s inspectors failed to gain access to Parchin, a key Iranian nuclear site. The failure of the meeting lowered hopes of a breakthrough in talks between world powers and Iran scheduled to take place in Moscow later this month.

Herman Nackaerts, the IAEA’s chief inspector, said “no progress has been made… and there is no point to finishing this round of talks,” referring to his meeting with Iran’s envoy to the IAEA Ali Asghar Soltanieh. He called the talks inconclusive and “disappointing,” and said Iran was going back on previous commitments it had made to inspectors. He added that a follow-up date for another meeting had not been set.

Soltanieh, however, defended his country and said there was “no obstacle” to striking a deal with the IAEA. Iranian President Mahmoud Ahmadinejad reinforced the assertion that it was not Iran, but the West, that was to blame for the breakdown. He also accused the West of “wasting time” in its talks with Iran and cited a letter sent by Saeed Jalili, Iran’s chief nuclear negotiator, to EU policy chief Catherine Ashton, that conveyed a similar message, Fars News reported.

The breakdown in IAEA-Iranian talks comes approximately three weeks after the moderate success of IAEA chief Yukiya Amano, who, after flying to Iran, claimed that the Islamic republic had agreed to grant the agency’s officials access to key facilities and scientists involved in the country’s nuclear program.

Located outside Tehran, Parchin is the site where explosives for nuclear weapons are believed to have been tested. Recent satellite photos have indicated that major renovation is underway in Parchin.