International Atomic Energy Agency chief Yukiya Amano said on Monday that satellite images indicated that buildings at an Iranian military site that the nuclear watchdog wants to visit are being demolished, according to Reuters.
Amano stressed the need for IAEA inspectors to visit the Parchin facility. His comments are likely to fuel speculation that Iran is trying to erase incriminating evidence before possibly granting access to the site.
The IAEA and Iran are scheduled to meet on June 8 in Vienna for more talks.
Amano said, "The satellite imagery indicates that these activities include the use of water, demolishing of buildings, removing fences and moving soil. These are some of the activities that we have observed through satellite imagery," according to Reuters.
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The Parchin site is of particular interest to the IAEA because of suspicions that it was used for testing related to nuclear weapons, said the BBC.
Talks between Iran and six world powers, Britain, the US, China, Russia, France and Germany, are also scheduled for next month, in Moscow. The world powers would like an agreement from Iran to stop enriching uranium and allow inspectors into its sites to confirm that, as Iran claims, its nuclear program is not geared toward creating a nuclear weapon.
An IAEA report released last November said Iran had "carried out activities relevant to the development of a nuclear device," reported the BBC.
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Meanwhile, Israel and the US are discussing further sanctions that could be imposed if the next round of talks fail to produce results, according to Agence France Presse.
US Treasury Undersecretary David Cohen told Israeli newspaper Haaretz, "If we don't get a breakthrough in Moscow there is no question we will continue to ratchet up the pressure."
Cohen, who is visiting Israel two weeks ahead of the talks in Moscow, said, "The sanctions are having an impact on Iran, but I also recognize that more needs to be done. And we are intent on doing more," according to the Associated Press.
On Sunday, Iran's supreme leader, Ayatollah Ali Khamenei said, "What Americans and westerners do is idiotic. They magnify the nuclear issue to cover up their own problems," according to Al Jazeera. He said the sanctions were not hampering Iran but merely deepening Iran's hatred of the West.
He warned, "If they take any miscalculated action, they will receive a thunderous blow," Al Jazeera reported.