U.S. analysts say they don't quite know yet what to make of reports that Libyan rebels are on the offensive in the capital, Tripoli. Aides say President Barack Obama is keeping tabs on the situation while vacationing in Martha's Vineyard, Mass.
Meantime, NATO says the situation in Libya is changing quickly and it's becoming more difficult to identify and engage targets for airstrikes as the uprising against Moammar Gadhafi gains momentum.
Libyan rebels said Sunday they were closing in on Gadhafi's main stronghold of Tripoli and a 600-strong unit is within 20 miles of the capital.
NATO spokesman Col. Roland Lavoie says he can't confirm that because the situation on the ground had become so fluid in recent days that it's difficult to track all developments.
He says much of the fighting now is concentrated in towns and villages, complicating the identification of targets. He says "there is no longer a traditional front line as we had in other phases of the conflict."