The United Nations' nuclear watchdog chief said Monday it is urgent to break the stalemate and a must to defuse the brewing confrontation surrounding the Iran nuclear issue, as Tehran is speeding up its nuclear plan in defiance of U.N. pressure.

"I am increasingly disturbed by the current stalemate and the brewing confrontation -- a stalemate that urgently needs to be broken, and a confrontation that must be defused," Mohamed ElBaradei, Director General of the International Atomic Energy Agency (IAEA), said in his introductory statement to the agency's board meeting.

The 35-nation board of governors of the IAEA started a five-day meeting here on Monday, with Iran's nuclear issue set to be the focus.

He told the meeting that Iran is expanding its uranium enrichment work despite demands for its suspension from the U.N. Security Council.

"The facts on the ground indicate that Iran continues to perfect its knowledge relevant to enrichment, and to expand the capacity of its enrichment facility," ElBaradei said, adding Iran has not taken the steps called for by the IAEA board nor responded to the demands of the Security Council.

ElBaradei said that the expansion arouses a key proliferation concern since the IAEA made no progress in its efforts to resolve outstanding issues relevant to the nature and scope of Iran's nuclear program.

The U.N. nuclear watchdog chief also accused Iran of continuing to put additional restrictions and limitations on IAEA's verification activities, while acknowledging Iran continues to provide IAEA access to its nuclear material and facilities, including the enrichment facility at Natanz, in accordance with its safeguards agreement.

"The Agency has been able to verify that no declared nuclear material in Iran has been diverted," ElBaradei said.

Despite the present deadlock, ElBaradei said that he still prefers a negotiated solution to the issue.

"I continue to believe that dialogue and diplomacy are ultimately the only way to achieve the negotiated solution foreseen in the relevant Security Council resolutions," ElBaradei said.

The United States is using the IAEA meeting to gather support for a third round of sanctions against Iran, which Iran is trying to avoid.

As Iran is steadily and resolutely pushing forward its nuclear program, concerns are growing that the United States could launch a surprise strike on its nuclear facilities, a move Washington has dismissed.

The United States and its Western allies accuse Iran of trying to develop nuclear weapons with its uranium enrichment project, while Iran insists that it only intends to generate electricity.