In an interview, Powell said that Washington supported the so-called "Geneva rule," the position of the Geneva group of top 10 contributors that heads of international organizations should not serve more than two terms, but that ElBaradei was welcome to stand for a third.

"We think the Geneva rule is a good rule: two terms," he said. "It's not been followed in the past on many occasions, more often than not, but we still think it's a good, useful rule. But we will make our judgement on specific cases when the time comes."

"I've told him that, Mohamed knows, we've talked about it," Powell said. "It's a good rule (but) he's free to offer his candidacy."

ElBaradei put his hat into the ring for a third term as director general of the International Atomic Energy Agency (IAEA) earlier this month despite the Geneva rule and the US position.

But ElBaradei, who is supported by IAEA board member China as well as the G-77 group of developing nations, may get a boost in October as he is an apparent favorite to win the Nobel Peace Prize after his work in monitoring nuclear activities in hot spots Iran, Iraq, North Korea and Libya.

The IAEA governing board met this week to draw up procedures for electing a new director general when ElBaradei's current four-year term expires on November 30 next year.

Applications for candidacies will close by December 31 and the board will seek to have the new director general named by a meeting in June 2005, in order to be formally elected at the next IAEA general conference in September

The director's general's new term would begin on December 1, 2005.

ElBaradei has been at the Vienna-based IAEA for two decades and since taking over as director general in 1997 he has become a world figure campaigning for nuclear non-proliferation.

He is a former law professor from New York University and once served as an Egyptian diplomat.