A clearly emotional ElBaradei told a press conference that had greeted him with sustained applause that "the prize would strengthen my resolve and those of my colleagues to speak the truth to power."

He said he had already talked with US Secretary of State Condoleezza Rice and that "we agree that we will have to continue to work together."

The United States has criticized ElBaradei for being too soft on Iran and opposed his continuing in office before he won a third four-year term in September as head of the Vienna-based International Atomic Energy Agency (IAEA).

ElBaradei said the people at the IAEA "have one set of objectives which is to make sure we have a world free from nuclear weapons that we have a world where terrorists do not get access to nuclear weapons."

The former Egyptian diplomat who has been director general of the IAEA since 1997 said the prize "gives me lots of pride and lots of responsibilities" and that it had came "as an absolute surprise."

ElBaradei said the Nobel committee had told him they had not called in advance to tell him of the honor since they wanted to avoid press leaks.

When he heard the news on television, he jumped to his feet with his wife "hugging and kissing and full of joy."

He said the committee wanted to give the IAEA "a shot in the arm to move forward" as it deals with non-proliferation problems in North Korea and Iran.

He later told CNN television, "I hope the Iranians will understand the prize to mean that the international community has full confidence in the IAEA to resolve the Iranian file."

He called for reforms to give the IAEA stronger investigative rights and for the UN Security Council to crack down when the IAEA refers countries to it for non-compliance with the nuclear Non-Proliferation Treaty (NPT).

ElBaradei said the Council, which took no action against North Korea in 2003, "has to back us up."

"We see our mandate very broadly," said ElBaradei, who has called for diplomacy to prevail despite the IAEA threatening to take Iran to the UN Security Council for possible sanctions over its non-compliance with the NPT.

"I'm here to further peace and development and I will continue to do that," he said.

"I see my job to be trying my very best to try to bring people together, to try to reconcile points of views, to try to resolve issues."

Asked to list IAEA successes, he said: "We managed to eliminate the Iraqi nuclear weapons program ... between 1991 and 1997."

"We are in fact the ones who detected the North Korean (nuclear) program as early as 1992" and "we have now come to the complete elimination of Libya's weapons program."

ElBaradei said progress had been made on the Iranian issue although important questions were still outsanding.

"One of the important achievements I'm proud of is how nuclear safety has improved in the last 10 to 15 years since Chernobyl," he said, referring to the explosion of a Ukrainian nuclear reactor in 1986.

"There are setbacks, there are hiccups, but this is part of life. But overall my colleagues and I will go to sleep tonight with a good feeling of satisfaction that finally our effort has been fully recognized."