TRIPOLI, Libya, March 28 (UPI) -- Libyan government forces used withering artillery and tank fire Monday to stymie rebel troops' efforts to solidify their advances on Sirte, observers said.
While the rebels had claimed to have taken Sirte, The New York Times quoted news reports as saying there was no sign of a takeover and the city seemed quiet. A stream of civilian cars and some military vehicles were seen leaving Sirte, bound for Tripoli, 225 miles away, the newspaper said.
Later in the day, rebel vehicles were seen making their way toward a checkpoint near Bin Jawwad, to the east of Sirte, the Times said.
"The regime still vastly overmatches opposition forces militarily," the Times said Gen. Carter F. Ham, the ranking American in the coalition forces, warned in an e-mail message. "The regime possesses the capability to roll them back very quickly. Coalition air power is the major reason that has not happened."
Ham said for the most part there had been few defections by Gadhafi loyalists.
Sirte, the hometown of Libyan leader Moammar Gadhafi and considered a strategic key for the rebels as they head toward Tripoli, was the target of coalition airstrikes Sunday night.
A rebel spokesman in Benghazi, the de facto base for the rebels, had said Sirte was in the rebels' hands but the claim couldn't be independently verified.
Rebel troops said they reclaimed a number of towns following airstrikes by U.S., British and French forces on government positions, the BBC reported Monday.
Government officials said the airstrikes gave the rebels an unfair advantage in the weeks-old conflict and accused international forces of going beyond the scope of the U.N. mandate to protect civilians.
Rebel forces claimed control of Ras Lanuf and appeared to have taken control of Brega and other cities as they move toward Tripoli, the nation's capital, CNN reported. The airstrikes, intended to prevent Gadhafi's forces from attacking civilian targets, allowed rebel forces to push west from Benghazi.
On Sunday, the North Atlantic Treaty Organization took full command of the coalition military operation in Libya.
Heavy explosions erupted Sunday in Tripoli, where Libyan officials said nearly 100 people were killed in a week of airstrikes by coalition forces, the BBC said. The statement could not be confirmed.
NATO Secretary-General Anders Fogh Rasmussen said the military alliance had the goal of protecting citizens "under threat of attack from the Gadhafi regime."
"NATO will implement all aspects of the U.N. resolution. Nothing more, nothing less," Rasmussen said. "We are already enforcing the arms embargo and the no-fly zone, and with today's [Sunday's] decision we are going beyond. We will be acting in close coordination with our international and regional partners to protect the people of Libya."
Libyan government officials countered that coalition forces only target troops loyal to Gadhafi, CNN said.
"The rebels are making their advance and no one is stopping them. And no one is even talking to them or saying, 'Where are you going?' or 'Why are you taking offensive positions and attacking the Libyan army and Libyan cities?'" government spokesman Moussa Ibrahim told reporters in Tripoli.
NATO, Ibrahim charged, was "starving the Libyan population to get Libya on its knees to beg for mercy."
On Monday, Libyan state television showed images of injured people in a hospital and of destroyed buildings, reporting the civilians were hurt when bombs struck Sabha. CNN said it was unable to independently verify the report.
As rebel forces pushed west, Misurata remained under siege by government forces, a witness told CNN. A doctor working at a hospital in Misurata said eight civilians were killed and 22 injured in violence Sunday.
In Washington, a Pentagon spokesman said the U.S. military began reducing the number of warships involved in the operation after the NATO takeover Sunday, the Times reported.
The official said at least one of the Navy submarines that fired Tomahawk missiles into Libya left the area, and a further reduction of naval forces was likely.
U.S. President Obama was to address the nation Monday night about the country's role in Libya.