A rebel fighter gestures in front of burning vehicles belonging to forces loyal to Libyan leader Muammar Gaddafi after an air strike by coalition forces along a road between Benghazi and Ajdabiyah March 20, 2011. [Agencies]

The US military, for now at the lead of the international campaign, is trying to walk a fine line over the end game of the assault. It is avoiding for now any appearance that it aims to take out Gadhafi or help the rebels oust him, instead limiting its stated goals to protecting civilians.

At the Pentagon, Navy Vice Adm. William E. Gortney underlined that strikes are not specifically targeting the Libyan leader or his residence in Tripoli. He said that any of Gadhafi's ground forces advancing on the rebels were open targets.

"If they are moving on opposition forces ... yes, we will take them under attack," he told reporters.

"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."

A military official said Air Force B-2 stealth bombers flew 25 hours in a round trip from Whiteman Air Force Base in Missouri and dropped 45 2,000-pound bombs.

What happens if rebel forces eventually go on the offensive against Gadhafi's troops remains unclear. Gortney would not say whether strikes would hit Libyan troops fighting back against rebel assaults.

US Defense Secretary Robert Gates said late Sunday that the US expects turn over control of the operation to a coalition headed by France, Britain or NATO "in a matter of days," reflecting concern that the US military was stretched thin by its current missions. Turkey was blocking NATO action, which requires agreement by all 28 members of the alliance.

Gadhafi vowed to fight on. In a phone call to Libyan state television Sunday, he said he would not let up on Benghazi and said the government had opened up weapons depots to all Libyans, who were now armed with "automatic weapons, mortars and bombs." State television said Gadhafi's supporters were converging on airports as human shields.

"We promise you a long war," he said.

Throughout the day Sunday, Libyan TV showed a stream of what it said were popular demonstrations in support of Gadhafi in Tripoli and other towns and cities. It showed cars with horns blaring, women ululating, young men waving green flags and holding up pictures of the Libyan leader. Women and children chanted, "God, Moammar and Libya, that's it!"

"Our blood is green, not red," one unidentified woman told the broadcaster, referring to the signature color of Gadhafi's government. "He is our father, we will be with him to the last drop of blood. Our blood is green with our love for him."

A rebel fighter looks at a burning vehicle belonging forces loyal to Libyan leader Muammar Gaddafi, after an air strike by coalition forces, along a road between Benghazi and Ajdabiyah March 20, 2011.[Agencies]