The US has stopped short of recognising Libya's National Transitional Council as the country's legitimate government.
The statement comes after the first visit to the White House by a senior member of the rebel council, which is pushing for international support.
Earlier, Col Muammar Gaddafi taunted Nato troops in an audio message on state TV, saying he was in a place where they "cannot reach" him.
State media says 11 Muslim clerics have been killed in a Nato air strike.
Mahmoud Jibril, deputy leader of the Benghazi-based National Transitional Council (NTC), met officials at the White House on Friday, including National Security Adviser Tom Donilon.
'You can't kill me'
In a statement, the White House said Mr Donilon had told Mr Jibril that the US viewed the council as "a legitimate and credible interlocutor of the Libyan people".
The US and Britain have not recognised the NTC as the true government of Libya - in contrast to France, Italy and Qatar.
White House spokesman Jay Carney said on Thursday that such a step would be "premature".
The US has said it is up to the Libyans to decide their government, not foreign powers.
There was some encouragement on Friday, however, for rebel hopes of accessing seized Libyan regime assets.
Mr Carney said the US was working with Congress to unblock some of the more than $30bn (£18.5bn) in frozen funds, so it could be used to aid the rebels.
Six large blasts - believed to have been Nato air strikes - were heard in the Libyan capital Tripoli late on Friday and early on Saturday morning.
They followed Libyan state TV's broadcast of an audio message by Col Gaddafi, pouring scorn on the alliance.
The Libyan leader thanked those outside Libya who had "expressed deep and strong concern, enthusiasm and love for me by carrying out all these contacts to enquire about my safety after hearing about the crusader, cowardly and treacherous missile attack".
"I say to the crusader cowards that I live in a place that you cannot reach and kill me in it because I live in the hearts of the millions," he added.
"Immortality is for the martyrs, and death, infamy and disgrace are for the treacherous agents and their cowardly masters."
Italy's foreign minister said earlier on Friday that Col Gaddafi had probably been wounded in Thursday's air strike on his Bab al-Aziziya compound and had fled Tripoli.
Earlier on Friday, state TV reported a Nato strike hit a boarding house in the eastern city of Brega, killing 11 imams and wounding 45 people.
A government spokesman said the victims were part of a larger group who had travelled to the government-held town from across Libya seeking peace talks in rebel-held Benghazi.
But rebel officials in Benghazi insisted there were no civilians at all in Brega, while a Nato spokesman said he did not know anything about an attack in Brega.