WASHINGTON (Reuters) - Libyan leader Muammar Gaddafi is not close to a military breaking point even though coalition strikes have seriously degraded his fighting power, the top U.S. military officer told Congress on Thursday.
"We have actually fairly seriously degraded his military capabilities. ... We've attrited his overall forces at about the 20- to 25-percent level," Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, told lawmakers.
"That does not mean he's about to break from a military standpoint, because that's not the case."
Mullen and Defense Secretary Robert Gates appeared before lawmakers almost two weeks after Western nations launched a military campaign aimed at protecting civilians in Libya from Gaddafi's loyalist forces.
Libyan rebels fought on Thursday for control of the eastern Libya oil town of Brega, a day after Gaddafi troops drove them back under a hail of rocket fire.
While President Barack Obama says Gaddafi must go, he and other U.S. officials have insisted the current military action authorized by the United Nations only allows for protection of civilians and enforcement of a no-fly zone over Libya.
"Deposing the (Gaddafi) regime, as welcome as that eventuality would be, is not part of the military mission," Gates said.
"In my view, the removal of Colonel (Gaddafi) will likely be achieved over time through political and economic measures and by his own people."
The comments came a day after revelations that Obama signed a secret order authorizing covert U.S. government support for rebel forces seeking to oust Gaddafi and media reports that clandestine operatives were gathering intelligence for air strikes.
Gates declined comment on any CIA role in Libya.
"I can't speak to any CIA activities but I will tell you that the president has been quite clear that in terms of the United States military there will be no boots on the ground," Gates said.
Gates and Mullen faced sharp questions from lawmakers who complained that Congress was not properly consulted before Obama forged ahead with military action in Libya.
(Reporting by Phil Stewart and Susan Cornwell; writing by Missy Ryan; editing by Vicki Allen)