The goal of removing Libya's Colonel Muammar Gaddafi from power will be actively pursued through non-military means, US President Barack Obama has announced.
"With the time and space that we have provided for the Libyan people, they will be able to determine their own destiny, and that is how it should be," he said during a speech intended to explain America's position on Libya.
"Of course, there is no question that Libya - and the world - will be better off with Gaddafi out of power," Mr Obama said.
The US president insisted humanitarian motives lie behind the Western-led offensive in the oil-rich country.
"I, along with many other world leaders, have embraced that goal, and will actively pursue it through non-military means. But broadening our military mission to include regime change would be a mistake.
"We have intervened to stop a massacre, and we will work with our allies and partners as they're in the lead to maintain the safety of civilians."
Mr Obama said Nato will take command of the arms embargo and no-fly zone from Wednesday.
Later today representatives from more than 40 countries meet Libyan opposition leaders to discuss future strategy.
"I said that America's role would be limited; that we would not put ground troops into Libya; that we would focus our unique capabilities on the front end of the operation, and that we would transfer responsibility to our allies and partners - we are fulfilling that pledge," he said.
"Our most effective alliance, Nato, has taken command of the enforcement of the arms embargo and no fly zone."
He added: "This transfer from the United States to Nato will take place on Wednesday.
"So for those who doubted our capacity to carry out this operation, I want to be clear: the United States of America has done what we said we would do," Mr Obama said.
He said America had a responsibility to act against Col Gaddafi when "confronted by this brutal repression and a looming humanitarian crisis."
Although Mr Obama mentioned humanitarian issues he also sought to link the Gaddafi regime to previous acts of terrorism, including the Lockerbie air disaster.
"He has denied his people freedom, exploited their wealth, murdered opponents at home and abroad, and terrorised innocent people around the world - including Americans who were killed by Libyan agents," Mr Obama added.
:: Hours before the address in Washington, Mr Obama took part in a video conference with leaders of Britain and France, which have been leading the coalition against Gaddafi - and the leader of Germany, which declined to take part in the effort.