“What is happening in Libya differs from the aim of imposing a no-fly zone, and what we want is the protection of civilians and not the bombardment of more civilians," he said, referring to Libyan government claims that allied bombardment had killed dozens of civilians. But reporters seeking proof have been offered none to account for even part of that number. Around 10 p.m., an explosion thundered from Colonel Qaddafi’s personal compound in Tripoli, and a column of smoke rose above it, suggesting that the allied forces had struck either his residence there or the nearby barracks of his personal guards. A group of foreign journalists were bused to the compound early on Monday morning and shown a building partially destroyed by a bomb. But those who attended reported no evidence of casualties.

Asked about the explosion, Vice Adm. William E. Gortney said in a Washington news conference that the United States was not trying to kill the Libyan leader. “At this particular point I can guarantee that he’s not on a targeting list,” he said, saying that the United States military was working to weaken his military capacity rather than removing him.

The chairman of the Joint Chiefs of Staff, Adm. Mike Mullen, also focused on those goals, talking about how allied forces had grounded Colonel Qaddafi’s aircraft and worked to protect civilians — both objectives stated by the United Nations Security Council in approving the military mission. “We hit a lot of targets, focused on his command and control, focused on his air defense, and actually attacked some of his forces on the ground in the vicinity of Benghazi,” Admiral Mullen told Fox News.

But the campaign may be balancing multiple goals. President Obama, Secretary of State Hillary Rodham Clinton and British and French leaders have also talked of a broader policy objective — that Colonel Qaddafi must leave power. In his comments on Sunday, Admiral Mullen suggested that objective lay outside the bounds of the military campaign, saying on NBC that Colonel Qaddafi’s remaining in power after the United States military accomplished its mission was “potentially one outcome.”