The head of the International Atomic Energy Agency is urging Tehran to accept a U.S. offer for dialogue and also allow better monitoring of its disputed nuclear program.  The move follows disputed presidential elections in Iran, which did not appear to shift Tehran's hardline stance.

IAEA Dir. General Mohamed ElBaradei is seen before the start of IAEA's board meeting in Vienna, Austria, 15 Jun 2009

In a speech in Vienna, International Atomic Energy Agency chief Mohamed ElBaradei expressed frustration at Tehran for failing to cooperate with inspectors trying to monitor Tehran's nuclear program.  Many countries suspect Iran is trying to build a nuclear bomb, while the Iranian government insists its program is for purely peaceful purposes.

In a report earlier this month, the IAEA concluded Iran had stockpiled a sizable amount of potential nuclear fuel, some scientists say enough to possibly make a bomb.

But ElBaradei said there is some cause for optimism.

"I am encouraged nonetheless by the new initiative of the United States to engage the Islamic Republic of Iran in a direct dialogue without preconditions and on the basis of mutual respect.  This gives reasons for hope that a genuine dialogue will lead to a comprehensive settlement of many security, political and economic issues spanning more than 50 years," he said.

ElBaradei urged Iran to respond to Washington's overture and said he hopes a dialogue between the two countries can begin as soon as possible.  

He made no mention of disputed presidential elections in Iran in which hard-line president Mahmoud Ahmadinejad was declared the winner.  

ElBaradei also criticized Syria for failing to fully cooperate in allegations it is also involved in questionable nuclear activities.  He also said he is deeply concerned about north korea's nuclear test.