The Obama administration expressed hope Monday that Libyan rebels have broken the military stalemate with forces loyal to Moammar Gadhafi, but stopped short of predicting rebel victory after months of inconclusive battles.
U.S. officials said they are encouraged by recent rebel advances near the capital of Tripoli and an apparent high-profile defection from Gadhafi's inner circle.
"It's becoming increasingly clear that Gadhafi's days are numbered," White House press secretary Jay Carney said, without elaborating on a weekend of significant advances by rebels from Libya's western mountains toward Gadhafi's stronghold of Tripoli. The rebels on Saturday pushed through to Zawiya, just 30 miles west of the capital on the Mediterranean coast, for the first time since the uprising against Gadhafi began in February.
Gadhafi's forces pushed rebels back from the center of Zawiya on Monday in fierce fighting to try to prevent the opposition from consolidating its gains.
Neither Carney nor State Department spokeswoman Victoria Nuland said the rebels now have the upper hand.
Nuland said the U.S. was watching with "considerable encouragement" the military progress of anti-Gadhafi fighters. She cited reports of the rebels taking of Gharyan and making advances in Zawiya and Tawargha, south of Misrata.
"What we are seeing is an effort by the rebels to choke off the access routes into Tripoli and to up the pressure on Gadhafi," she told reporters in Washington.
But some U.S. officials say the rebels may now have enough momentum to wrest full control of the country. The officials spoke on condition of anonymity because they were not authorized to discuss the fast-moving developments.
Other U.S. officials, including military officials, say it is too early to tell whether they will be able to hold onto the gains they have made in Tripoli's backyard.
One senior military official said the Pentagon is not ready to declare the opposition forces have reached a turning point, although it is not insignificant that they appear to have been able to hold the ground so far.
The Pentagon has been seriously considering a request from commanders to increase the number of intelligence and reconnaissance drones provided to the NATO forces.
As of Monday, the U.S. had flown more than 1,100 strike operations, dropping bombs more than 230 times since April 1. There have been 88 Predator drone strikes.
Asked about the possible defection to Egypt of Libyan Interior Minister Nassr al-Mabrouk Abdullah, Nuland said she did not know his intentions.
A Tunisian security official said Abdullah had defected after entering Tunisia by land on Saturday and then flying to Cairo and entering on a tourist visa.
"Senior members of his government seem not to want to stand with him in Libya but are voting with their feet," said Nuland.
In one sign of perhaps greater U.S. optimism, Nuland noted that Libya's opposition movement, the Transitional National Council, was reforming itself after the killing last month of military commander Abdel-Fattah Younis. And she spoke of the process as if it were paving the way for a responsible, post-Gadhafi government.
"We look for that new government to meet these high standards of unity, inclusiveness, democratic commitment," Nuland said. "It is our hope and expectation that it will be a strong, new government."
Associated Press writer Bradley Klapper contributed to this report.