Outgoing IAEA chief Mohamed ElBaradei fired a parting shot at Iran here on Thursday, saying efforts to verify the exclusively peaceful nature of its nuclear program had reached a dead end, as the UN atomic watchdog considered censuring Tehran.

ElBaradei has been often accused during his 12 years as head of the International Atomic Energy Agency of being too soft on Iran.

But as the end of his term neared –the Egyptian diplomat steps down next week –and the IAEA no closer to knowing the true nature and extent of Tehran's nuclear ambitions, Elbaradei has toughened his language in recent weeks.

His tone has become noticeably sharper after the Islamic Republic snubbed his own compromise deal on the supply of fuel for a nuclear research reactor in Tehran.

Addressing the IAEA's 35-member board of governors at the start of a two-day meeting, ElBaradei criticised Iran for long concealing a second uranium enrichment plant in Fordo, near the holy city of Qom.

Iran's failure to notify the agency of the existence of the plant near Qom until September 2009 "was inconsistent with its obligations", he complained.

"Iran's late declaration of the new facility reduces confidence in the absence of other nuclear facilities under construction in Iran which have not been declared to the agency," he said.

And he complained that there has been no movement for "well over a year" from Iran on allegations it had previously been engaged in studies on nuclear weaponisation.

"It is now well over a year since the agency was last able to engage Iran in discussions about these outstanding issues," he said. "We have effectively reached a dead end, unless Iran engages fully with us."

-AFP/NOW Lebanon