Libyan rebels have killed more than 300 troops loyal to leader Muammar Gadhafi in the western city of Misrata in the past two days, opposition website Libya al-Youm reported on Tuesday.
NATO launched fresh airstrikes to weaken Gadhafi's forces, state media said, as many Libyans have begun to fear that the fighting between rebels and government forces will go on for months.
An estimated 20 Gadhafi loyalists have been captured, among them two army majors - including the second in command of the elite Khamis Gadhafi brigade, Libya al-Youm reported.
There were also civilian casualties, with 12 people killed in Misrata on Monday, and 57 wounded, according to broadcaster Al Jazeera.
On Tuesday, the United Nations said it helped deliver more than 500 tons of food to Misrata, which is the country's third-largest city and a key gateway to the capital city of Tripoli.
Rebel spokesman Abdul Hafiz Ghoga told the German Press Agency dpa by telephone that Gadhafi's forces have not respected the ceasefire that they promised in Misrata.
"The rebels have made good gains in the center of the city but Gadhafi's forces are still on the outskirts. The statement they made regarding a ceasefire there has no truth to it," said Ghoga.
Despite gains made by the rebels in the last few days of fighting, frustrations and fears were coming to the surface among residents in the coastal city of Derna, located between the rebel stronghold of Benghazi and Tobruk town.
"If we don't see progress soon, people will get very frustrated," said Iman El Kuf, who used to work in the tourism industry in Derna.
"There are already pockets of resistance against the rebel movement. After dark, they come out. Perhaps if the rebels do not advance soon, others might join them," she said.
Another resident, Mohamed Founi, complained that many people can't find jobs and that schools were still closed. He said one liter of oil, which was sold for 1.5 Libyan dinars before the revolution now costs up to 3.5 dinars.
NATO said Tuesday that its forces launched attacks a day earlier that struck at a training facility near Misrata, as well as vehicles and tanks in Tripoli. Three ammunition depots were also destroyed in the area around Gadhafi's hometown of Sirte, according to the NATO statement.
Government officials said an attack on the buildings in Gadhafi's Bab Al Aziziya compound was an assassination attempt, something which NATO forces have denied.