"I think that the IAEA board of governors sent a very clear message that Iran must cease its pursuit of nuclear weapons, and answer questions, which the board has raised, and suspend its enrichment activity," he said. "We were very pleased by this consensus, by the closing of whatever gaps existed, in terms of tactical approaches, and we should all expect that Iran should follow the obligation and cooperate fully with the IAEA. The clock is ticking down now on Iran towards the next meeting."

The 35-member IAEA board is scheduled to meet again in November to decide whether the Iran issue should go to the U.N. Security Council for possible sanctions.

Secretary Abraham was in Vienna for a conference on combating nuclear smuggling. He said the United States supports a project, together with Russia and the IAEA, to return spent fuel from old reactors to the country of origin.

"We recognize that there is a world in which terrorists are attempting to gain access, either to nuclear weapons, or materials, and we intend to stop them," he said.

This month, the United States, Russia and the IAEA worked to return highly-enriched uranium from Uzbekistan to a nuclear facility in the Russian city of Dmitrovgrad. There, it will be blended down to low-enriched uranium and used in power plants.

The enriched uranium was used in a Soviet-designed research reactor near Tashkent, described as the largest of its kind in Central Asia.

The removal of such potentially dangerous nuclear material from Uzbekistan is seen as especially important, since the country has become a target for terrorists.

In July, suicide bombers set off explosives outside the U.S. and Israeli embassies in the Uzbek capital, Tashkent. The government blamed foreign Islamic extremists for the attacks.

There are about 130 research reactors around the world running on weapons-grade uranium.