The head of the International Atomic Energy Agency on Monday told North Korea to end its course of nuclear confrontation. He also urged Iran to agree to Washington's offer of direct dialogue and called on Syria to cooperate with his agency's investigation.

Mohamed ElBaradei's comments at the opening session of the U.N. agency's 35-nation board meeting dovetailed with world concerns about the two nations.

North Korea has announced it is expanding its weapons-capable program after exploding its second test atomic bomb last month. And beyond the immediate concerns of serious street unrest in Tehran, the re-election of hardline Iranian President Mahmoud Ahmadinejad has clouded hopes that Tehran may be ready to end its nuclear defiance and meet U.N. Security Council demands that it curb its uranium enrichment.

Iran has been referred to the Security Council on suspicions of hiding nuclear activities and fears it could retool its enrichment program from making material for nuclear power into weapons-grade uranium used for warheads.

Allegations against Syria are still being discussed in meetings of the Vienna-based IAEA.

Syria, like Iran, denies any hidden nuclear agenda but it, too, is under IAEA investigation. The U.S. claims Damascus has been hiding a nuclear program that came to light in September 2007 after Israeli warplanes destroyed what Washington says was its centerpiece — a nearly finished reactor built with North Korean help.

Except for a brief period that ended last year when North Korea broke off talks and resumed its nuclear activities, agency inspectors have been shut out of the country since 2003. The agency has more overview of Iran and Syria, which both remain within the nonproliferation fold as members of the agency.

But IAEA attempts to investigate the allegations against Iran and Syria have also been deadlocked. For over a year, both nations have rebuffed agency requests for visits and information meant to help prove or disprove the allegations against them, effectively deadlocking the two investigations.

ElBaradei spoke of the impasse in his opening comments.

"There has been no movement by Iran on outstanding issues which need to be clarified to exclude the possibility of military dimensions to Iran's nuclear program," he said, alluding to U.S. and other intelligence shared with the agency that suggests Tehran had developed plans for elements of a weapons program. As well, "Iran has not implemented any of the measures called for by the Security Council," he added, in an indirect reference to its refusal to freeze enrichment.

Noting newfound American willingness to talk directly to the Islamic Republic on nuclear and other issues of contention, ElBaradei urged Tehran to "respond to the U.S. initiative with an equal gesture of goodwill and trust-building."

On Syria, ElBaradei criticized the limited information and access" provided by Damascus, noting that the IAEA investigation was unable to make progress as a result

And he expressed concern over North Korea's second nuclear test. "This," said ElBaradei, "is a wrong step in the wrong direction, which has again created an environment of confrontation."