United Nations: The U. nuclear chief said Monday that Iran is not cooperating with an investigation into suspected secret work on nuclear weapons.

Yukio Amano told the N General Assembly that talks between the International Atomic Energy Agency and Iran have intensified this year after an IAEA report in November 2011 said it had “credible information that Iran had carried out activities relevant to the development of a nuclear explosive device,” he said.

“However, no concrete results have been achieved so far,” Amano said.

While the IAEA continues to verify that Iran’s declared nuclear material is not being diverted from peaceful purposes, “Iran is not providing the necessary cooperation to enable us to provide credible assurance about the absence of undeclared nuclear material and activities,” Amano said.

“Therefore, we cannot conclude that all nuclear material in Iran is in peaceful activities,” he said.

But the IAEA director general said “the agency is firmly committed to intensifying dialogue with Iran.”

“We will continue negotiations with Iran on a structured approach,” he said. “I hope we can reach agreement without further delay.”

Iran has repeatedly denied any interest in possessing nuclear arms, but the international community fears that Tehran may turn its peaceful uranium enrichment program toward weapons making - a concern that is growing as the government expands the number of machines it uses to enrich its stockpile of enriched uranium.

As those fears grow, so does concern that Israel could carry out its threats to attack Iran’s nuclear facilities before that nation reaches the bomb-making threshold.

Iran’s UN Ambassador Mohammad Khazaee reiterated his country’s position, that it has a right to develop nuclear energy for peaceful purposes and rejected the claims in the IAEA report saying they are “not credible” and based on “forged reports” provided by Israel and the United States.

Amano also urged the Syrian government to respond to questions about a building destroyed by Israeli warplanes at the Dair Alzour site in the Syrian desert in 2007. The IAEA has said the building was “very likely” the covert site of a nuclear reactor.

The United States asserted more than four years ago that the bombed target was a nuclear reactor, but Syria has repeatedly denied allegations of any covert nuclear activity or interest in developing nuclear arms, saying the building was a non-nuclear military site.

Amano also reported on prospects for convening a conference in 2012 on the establishment of a Middle East zone free of nuclear weapons, which the 189 nations that are parties to the NPT called for in May 2010.

The IAEA held a forum on the possible relevance of creating such a zone in November 2011, he said, but “there remain fundamental differences of views among countries of the region on this important issue and it has not been possible to make further progress.”

Israel is not a party to the NPT and has long said a full Arab-Israeli peace must precede such weapons bans.

Thomas Mayr-Harting, head of the European Union delegation to the United Nations, said it is holding a seminar in Brussels on Monday and Tuesday where “an open exchange of views on all aspects related to the creation” of a nuclear weapons-free zone in the Mideast will take place.