The US says it is ready to support a third term for Mohamed ElBaradei as head of the UN's nuclear watchdog.
ElBaradei's position on Iran has irked the US
The Bush administration had called for him to step down at the end of his second term this year, after falling out with him over Iraq and Iran.
The US has been the only country to oppose Mr ElBaradei continuing at the International Atomic Energy Agency.
But the US now says it will vote for him, following a meeting between Mr ElBaradei and the secretary of state.
Condoleezza Rice indicated earlier that the US could back him if he toughened his stance on Iran.
"We expect that when the vote comes up in the (IAEA) board of governors on this issue we will join the consensus," US state department spokesman Sean McCormack said.
'Jury still out'
The 62-year-old Egyptian lawyer is the only candidate for the post, which he has held since 1997.
Joins IAEA in 1984, becomes chief in 1997
Favours diplomacy in dealing with nuclear rows
Has clashed with the US over the Iran issue
2004 Nobel Peace Prize nominee
Thursday's meeting with Ms Rice was being seen as something of a job interview for Mr ElBaradei, the BBC's Jane O'Brien in Washington says.
They agreed on the urgency of halting the spread of nuclear weapons technology, the state department spokesman said, according to the Associated Press.
Ms Rice has made it clear that US support will depend on whether the two can reach agreement over the IAEA's position on Iran.
The US wants Mr ElBaradei to toughen up and report Iran to the UN Security Council for trying to hide its nuclear activities.
But Mr ElBaradei has said the "jury is still out" on whether Tehran is secretly developing nuclear weapons, because he has no clear proof.
However, he recently stressed that it was now up to Iran to dispel doubts about its programme "through absolute transparency measures and co-operation with the [IAEA]".
The IAEA says Mr ElBaradei will not strike a deal to secure his position. However, his decision to announce a progress report next week on the agency's two-year investigation into Iran's nuclear programme is seen by some analysts as a move aimed at winning favour with Washington.
The new IAEA head is expected to be chosen when the agency's 35-nation board of governors meets on Monday.