Tripoli, Libya (CNN) -- In an effort to hold onto the few remaining places they still control in Libya, Moammar Gadhafi's forces put up stiff resistance again Saturday as revolutionaries fought to wrest control of the loyalist strongholds of Sirte and Bani Walid.
Fierce fighting erupted in the coastal city of Sirte, the birthplace of Gadhafi and home to his tribe.
At least eight anti-Gadhafi fighters were killed and 31 others were wounded, said Ali Gheliwan, a spokesman for the Misrata Military Council.
NATO planes, meanwhile, bombed targets in the Sirte area Friday. Gadhafi's forces unleashed hails of gunfire, using snipers in tall buildings to target their enemies.
Expected support from Sirte residents for the anti-Gadhafi forces did not materialize, as loyalists fought house to house with unexpected intensity. The revolutionaries were forced to retreat after the chaotic urban warfare.
Despite such challenges, Col. Ahmed Bani of the National Transitional Council predicted it will not take long for all of Libya to be under the anti-Gadhafi forces' control. He claimed, for instance, that Sirte's airport and the nearby Ghardabiya air base already have switched hands.
"I can say that things will change drastically in the upcoming days in Sirte and Bani Walid," the group's spokesman said in his first press conference Saturday from Tripoli.
Bani claimed that part of Bani Walid, another loyalist hub located in a mountainous area southeast of Tripoli, is also under anti-Gadhafi forces' control despite stiff opposition. City residents had been fleeing ahead of the offensive, which followed a 48-hour warning.
"We were attacked by rocket-propelled grenades and snipers from the mountains," he said. "We repositioned, and we can say that the north is under control of our revolutionaries."
However, Salah Beniran, a field commander for anti-Gadhafi forces in Bani Walid, said Gadhafi loyalists have taken some residents hostage, "and they are heavily armed with missiles, rocket-propelled grenades and machine-gun-mounted trucks."
"They encircled us from the eastern front," Beniran said.
The clashes contrasted with the scene in several Sahara Desert towns more sympathetic to the revolution, where people cheered the anti-Gadhafi forces as they made their way toward the southern city of Sabha.
In Shati, there was no combat; only a peaceful transfer of power, perhaps the first in the eight-month uprising. In the morning the tiny town had been under Gadhafi's grip. By afternoon, no more.
Residents fired their guns in celebration and burned the green flags of the former regime.
They welcomed the ordinary Libyans -- teachers, doctors, engineers -- who dropped everything to join the fight against Gadhafi. They were rebels once. Now they were the armed wing of Libya's new governing body, the National Transitional Council.
But the situation was different in Sabha, a diehard pro-Gadhafi city in southwestern Libya.
Anti-Gadhafi forces took control of the Al-Birak air base in the city Saturday, but the battle was far from over, Bani said.
"There has been fierce fighting for a while now," the spokesman said. "The people in Sabha are from different tribes. There are a big number of loyalists who escaped from other cities, and they are still fighting."
Bani issued what he called a "final call" for all Gadhafi loyalists to switch sides and join his group, warning that -- if they do not -- they risk being charged with treason."
He added he hopes Gadhafi is in one of the three cities -- Sirte, Bani Walid and Sabha -- still in the throes of heavy fighting Saturday and not yet held by his forces, so that he can be taken into custody.
"We hope he is ... so we can arrest him and give the world a break from his evils," the colonel said. "(Up) until now, there is no certain information about his location."
As these battles continued to rage in Libya, the international community came together to pledge support for the war-torn nation's new leaders in Tripoli.
The United Nations Security Council unanimously adopted a resolution Friday to establish a support mission in Libya for an initial period of three months and to take other measures to help the country get back on its feet.
The mission's mandate includes restoring public security and order and promoting the rule of law, beginning efforts to write a constitution and set up elections, promoting and protecting human rights, and thawing the assets freeze that had been imposed on the Gadhafi's government.
The resolution further asks U.N. Secretary-General Ban Ki-moon to report on its implementation in two weeks and every month thereafter, or more often if he sees fit.
CNN's Jill Dougherty, Mohamed Fadel Fahmy, Ben Wedeman, Richard Roth and Mick B. Krever contributed to this report.