Last Updated 5:37 p.m. ET
A U.S.-led coalition has succeeded in scattering and isolating Libyan strongman Muammar Qaddafi's forces after a weekend of punishing air attacks, Pentagon officials say, and a no-fly zone implemented over the eastern part of the country will be extended to the capital, Tripoli.
Libyan TV reported that Tripoli had come under a new attack by international airstrikes. Anti-aircraft fire erupted in the city several hours after nightfall Monday as television made the announcement. It was not immediately known what the strikes were targeting.
Gen. Carter Ham, U.S. commander in the region, said the American role in the three-day old air assault to degrade Libya's military capability already had begun to decline, with the overwhelming share of Monday's missions flown by pilots from other countries in the coalition. Whereas about 50 percent of the approximately 60 air missions flown on Sunday were by U.S. pilots, the "overwhelming" share were by non-U.S. pilots on Monday, Ham said.
The success of the coalition assault has already produced tangible results, Ham said.
"Air attacks have succeeded in stopping regime ground forces from advancing to Benghazi, and we are now seeing ground forces moving southward from Benghazi," Ham said. "Through a variety of reports, we know that regime ground forces that were in the vicinity of Benghazi now possess little will or capability to resume offensive operations."Ham said coalition jets fired 12 more cruise missiles at Libyan missile, command and air defense sites as they continued to press a no-fly zone over the North African nation.
A mix of coalition aircraft was enforcing the new zone, and officials said they saw no indications that Qaddafi had tried to fly any of his planes.
Asked what the coalition knows about the whereabouts of Qaddafi, Ham said essentially, not much. Speaking by video conference from his headquarters in Germany, Ham told Pentagon reporters that the international coalition is focusing on knocking out Libya's ability to command and control its forces.
In a press briefing Monday, Ham ruled out providing close air support for opposition fighters. He said their mission was to protect civilians. He also said there is no direct coordination with those rebels.
Navy Vice Adm. William E. Gortney, staff director for the Joint Chiefs of Staff, told a Pentagon news conference Sunday there is no evidence civilians in Libya have been harmed in the air assault, code named Odyssey Dawn. Gortney also said no allied planes have been lost, and all pilots have returned safely from missions that used stealth B-2 bombers, jet fighters, more than 120 Tomahawk cruise missiles and other high-tech weapons.
Following Sunday's strike on a building at Col. Qaddafi's Tripoli compound, Gorney said that Qaddafi is not a target of the campaign, but he could not guarantee the Libyan leader's safety.
"We judge these strikes to have been very effective in significantly degrading the regime's air defense capability," Gortney said. "We believe his forces are under significant stress and suffering from both isolation and a good deal of confusion."
But Gortney did not rule out the possibility of further attacks aimed at preventing Qaddafi from attacking civilians in Libya and enforcing a no-fly zone.
British Prime Minister David Cameron said Monday that by neutralizing Libyan air defenses, the coalition forces helped avert "a bloody massacre in Benghazi" when Qaddafi failed to abide by a cease-fire.
U.S. and allied aircraft are now patrolling the no-fly zone looking for targets of opportunity - Libyan ground units that are threatening rebel-held cities or any locations that can be identified as command centers for Qaddafi forces, reports CBS News national security correspondent David Martin.
That is apparently what happened Sunday with the attack on a building in Qaddafi's compound in Tripoli. U.S. Intelligence picked up signals that it was being used as a command center and a British submarine off the coast of Libya launched this cruise missile against that target.
Qaddafi and his residence are not on a list of targets to be hit by coalition aircraft, Gortney said. But Qaddafi won't be safe "if he happens to be at a place, if he is inspecting a surface-to-air missile site and we don't have any idea that he's there or not," Gortney said.
Defense Secretary Robert Gates said the U.S. expects to turn control of the mission over to a coalition -- probably headed by either the French and British or by NATO -- "in a matter of days."
Late Sunday, however, NATO's top decision-making body failed to agree on a plan to enforce the no-fly zone over Libya, although it did approve a military plan to implement a U.N. arms embargo.
On Saturday night, three Air Force B-2s, launched from Whiteman Air Force Base in Missouri, dropped precision munitions on an airfield near the city of Misurata, destroying hardened military aircraft shelters while avoiding commercial structures nearby. A military official said the B-2s flew 25 hours in a round trip from Whiteman and dropped 45 2,000-pound bombs.
And fifteen Air Force and Marine Corps aircraft, along with jets from France and Great Britain, hit a heavy infantry unit advancing on the rebel capital Benghazi. "To protect the Libyan people, we took them under attack," Gortney said.
Gortney said the coalition had control of the air space between Benghazi and Tripoli, Libya's capital. "The no-fly zone is effectively in place," he said. "Anything that does fly that we detect, we will engage."
The allied air strikes have been given a morale boost to rebels in Benghazi, who now feel that momentum is back on their side, CBS correspondent Mandy Clark reports. But the international help hasn't removed all the dangers on the ground and the battle for Benghazi is ongoing, with elements of Qaddafi loyalists engaging rebels in street battles. But the bulk of government fighters are believed to have retreated behind Ajdabiya, 100 miles from Benghazi.
Rebels are thankful for the protections of above, but they say the ground battle is one they must fight on their own. And that's the position the U.S. supports.
Earlier Sunday, Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said the goals of the operation are to protect civilians from further violence by pro-Qaddafi forces, while enabling the flow of humanitarian relief supplies. But it was unclear how long the military effort would continue or on what scale.
That uncertainty led to criticism from senior Republicans in Congress.
House Speaker John Boehner said that the Obama administration "has a responsibility to define for the American people, the Congress and our troops what the mission in Libya is" and how it will be accomplished.
Rep. Howard P. "Buck" McKeon, the Republican chairman of the House Armed Services Committee, said Mr. Obama needs to tell the American public "to what extent military force will be used and for how long."Gen. Norton Schwartz, the Air Force chief of staff, told lawmakers last week that intelligence-gathering and surveillance aircraft being used in Iraq and Afghanistan may be shifted to Libya. These aircraft are limited in number, Schwartz said, and "trade-offs" may have to be made.
Schwartz said he expected the supersonic F-22 Raptor -- a jet fighter yet to be used in combat -- to play a prominent role in the initial attacks on Qaddafi's forces. With its stealth design, the F-22 can evade radar and has advanced engines that allow it to fly at faster-than-sound speeds without using gas-guzzling afterburners.
But Gortney would not say whether the F-22 had been or will be used. The Air Force has said only that the B-2 and F-15 and F-16 fighters participated in the operation.
As of Sunday, Gortney said members of the coalition included the U.S., Great Britain, France, Canada, Italy, Belgium and Qatar. More are expected to join, but Gortney said those countries, and not the U.S., would make that announcement.