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The United States accused Iran (search) on Wednesday of "cynically" pursuing nuclear weapons, saying Tehran's claims that its aims are peaceful constitute willful deceit of the world.

The comments by Jackie Sanders, chief U.S. delegate to the International Atomic Energy Agency (search) board of governors, were in response to an IAEA update on Iran's nuclear record after more than two years of examination by the agency.

Sanders characterized Tuesday's IAEA report as a "startling list of Iranian attempts to hide and mislead and delay the work" of agency experts probing the country's nuclear activities.

"The IAEA is still not able to provide assurances that Iran is not pursuing clandestine activities at undeclared locations," Sanders said. Tehran, she said, was guilty of "cynically" manipulating the Nonproliferation Treaty and related programs "in the pursuit of nuclear weapons."

The IAEA review noted that while Iran allowed inspectors an initial visit to the Parchin military complex (search) in mid-January, the experts' visits were limited to one site and only five buildings on that site. A new request to revisit another part of the site was refused by Iran on Sunday, he added.

The United States alleges Iran may be testing high-explosive components for nuclear weapons by using an inert core of depleted uranium at Parchin as a dry run for a bomb that would use fissile material.

Iran asserts its military is not involved in nuclear activities, and the IAEA has found no firm evidence to the contrary. The agency also has not been able to support U.S. assertions that nearly two decades of covert nuclear programs discovered more than two years ago were aimed at making nuclear weapons — not generating electricity, as Tehran claims.

A separate Iranian decision outlined in the review — to block any further probing of possible dual use equipment at the Lavizan-Shian site near Tehran — appeared particularly galling to the IAEA because it effectively shut down one area of the agency's inquiry.

The State Department last year said Lavizan-Shian's buildings had been completely dismantled and that top soil had been removed from the site in attempts to hide nuclear weapons-related experiments.

The review also revealed that Iran continues to build a heavy water reactor in the city of Arak that can produce plutonium despite agency requests to cease construction on the facility.

It also noted delays by Iran in informing the agency that it was building tunnels in the central city of Isfahan for nuclear storage and blips in its commitment to totally freeze all activities related to uranium enrichment.

Iran has suspended work on its enrichment program pending negotiations with France, Germany and Britain. But it has repeatedly said the freeze is short-term, despite hopes that it will fully scrap its plans.

Sanders said Wednesday that nothing short of "full cessation and dismantling" of enrichment activities "can give us any confidence" Iran is no longer producing nuclear weapons.

But Iran insists on its right to enrichment.

"This is something that is not on the table and will not be on the table," senior Iranian envoy Sirius Nasseri told reporters, saying his country had "gone through blood and sweat and tears" to develop the program.

A separate statement by the three European nations engaging Iran expressed "serious concern" at some of the developments outlined by the report.

North Korea also was on the agenda Wednesday of the agency's 35-nation board. Delegates were trying to find common language on a statement that urges the North to return to negotiations and end nuclear threats that is firm without further alienating the reclusive country.

Stepping up their efforts to get the North back to the table, Chinese Deputy Foreign Minister Wu Dawei met Wednesday in Seoul with South Korean Foreign Minister Ban Ki-Moon.

The United States and South Korea have urged China to play a more active role in persuading North Korea to return to the six-party talks, which also include Russia and Japan. Those efforts gained urgency after the North's unconfirmed claim on Feb. 10 that it has built nuclear weapons.

The United States is scheduling a trip by Secretary of State Condoleezza Rice late this month to Northeast Asian countries, including South Korea, as part of efforts to revive the nuclear talks, Ban told reporters.