Updated at 4:15 p.m. edt
NATO acknowledged a malfunctioning guided missile probably was responsible for the deaths of nine civilians in Tripoli overnight.
"NATO regrets the loss of innocent civilian lives and takes great care in conducting strikes against a regime determined to use violence against its own citizens," NATO commander Lt. Gen. Charles Bouchard said in a statement.
"Although we are still determining the specifics of this event, indications are that a weapons system failure may have caused this incident," he added.
The limping Gadhafi regime took advantage of the rare botched bombing, hoping to rile up the divided Tripoli. However, still no sign of the despot-in-hiding Moammar Gadhafi.
Outgoing Defense Secretary Robert Gates was opposed to the no-fly zone over Libya ahead of the NATO air campaign, but today he showed he is in lockstep with President Obama, defending the administration's compliance with the War Powers resolution.
"I believe that President Obama has complied with the law consistent in a manner with virtually all of his predecessors," Gates told the "Fox News Sunday" program.
The highly regarded Pentagon chief, whose distinguished career of public service has included serving in both Republican and Democratic administrations, took the administration's position that the no-fly zone with no U.S. troops on the ground does not amount to hostilities.
Today marks the 90-day deadline for withdrawing forces from Libya under the War Powers resolution of 1973, but since the administration contends that resolution does not apply to Libya, the U.S. will continue to play the key support role in that mission.
"The way I like to put it is, from our standpoint at the Pentagon, we're involved in a limited kinetic operation. If I'm in Gadhafi's palace, I suspect I think I'm at war," Gates said.
Gates' defense of the administration's position came just two days after The New York Times reported it was a split decision among Obama's lawyers on the question of whether the War Powers resolution applies to the no-fly zone over Libya.
Obama, a Harvard Law-educated legal scholar, sided with White House Counsel Robert Bauer and State Department legal adviser Harold Koh, who ruled the U.S. mission in Libya did not amount to "hostilities," and therefore the war Powers resolution does not apply in this case.
Those who argued in favor of the War Powers resolution included Pentagon General Counsel Jeh Johnson and acting head of the Justice Department's Office of Legal Counsel Caroline Krass.
As divided lawmakers in Washington argue over the legalistic ramifications of the Libya mission, the Gadhafi regime suggested NATO bombed a home overnight, killing nine civilians. NATO is looking into the claim.
Moammar Gadhafi, meanwhile, continues to hold on to power in Tripoli while hiding from NATO's warplanes.
"NATO will be defeated," Gadhafi said in another telephone call to State Run TV Friday "They will pull out in defeat."