Al-Brega, Libya (CNN) -- Libyan rebels continued their westward advance Sunday, claiming that they gained operational control of another key city, Ras Lanuf.
Rebel forces told CNN that forces loyal to Libyan leader Moammar Gadhafi pulled back from the city, but CNN has not yet independently confirmed the claim.
If true, it would signify that the rebel forces have reclaimed all of the territory they lost to Gadhafi's forces at the start of the war. The opposition comeback was paved in part by coalition airstrikes designed to stop the killings of civilians, and that have hit Gadhafi's forces.
Earlier Sunday, the rebels appeared to have taken control of the key oil town of al-Brega, a CNN team on the scene observed.
Some opposition fighters focused on securing the city's entrance Sunday while others traveled in trucks heading west, encountering little resistance along the way.
Reinvigorated after regaining control of the nearby city of Ajdabiya on Saturday, rebel troops had set their sights on al-Brega -- which has a large oil refinery and a natural gas plant.
After Ras Lanuf, the next major city on the highway toward the capital of Tripol is Gadhafi's hometown of Sirte. Rebel forces told CNN they expect a long and bloody battle there.
Determined to topple Gadhafi's nearly 42-year reign, rebels pledged to continue the westward march to Tripoli as coalition airstrikes continued in the North African nation.
"The dictator has chosen to take the bloody road. ... We encourage him to leave or we will force his removal," opposition spokesman Col. Ahmed Omar Bani told reporters Saturday.
State television reported that civilian and military locations in Sabha and Gadhafi's birthplace of Sirte were bombed overnight.
Coalition airstrikes continued as NATO prepared to take command of the Libya mission this weekend.
Coalition officials say the airstrikes are aimed at enforcing a no-fly zone and protecting civilians in Libya.
But Libyan government officials countered that claim, arguing that coalition forces only target troops loyal to Gadhafi.
"The aim is to push our armored forces city by city. This is the objective of the coalition now. It is not to protect civilians," Libyan Deputy Foreign Minister Khaled Kaim said Saturday.
Coalition planes flew at least 96 airstrike missions in a 24-hour period that ended Saturday, according to statistics released by the Pentagon, and leaders reported damage to Gadhafi's ground forces.
Opposition fighters chanted gratitude for the coalition's support after they wrested control of Ajdabiya, considered a gateway to Libya's vast oil fields and a stopping point en route to the rebel stronghold of Benghazi.
They were confident that with protective air power, they would be able to hold onto the city they had captured once before but lost to Gadhafi's army.
The coalition's air campaign continued Saturday, further limiting loyalist movements. French warplanes destroyed at least five Libyan combat planes and two helicopters over a 24-hour period, the Ministry of Defense said.
Explosions and airstrikes were also reported in Tripoli, Tarhunah and Misrata.
U.S. President Barack Obama defended America's leadership in the international coalition in his weekly radio address Saturday.
"The United States should not -- and cannot -- intervene every time there's a crisis somewhere in the world," Obama said. "But I firmly believe that when innocent people are being brutalized; when someone like Gadhafi threatens a bloodbath that could destabilize an entire region; and when the international community is prepared to come together to save many thousands of lives -- then it's in our national interest to act. And it's our responsibility. This is one of those times."
But Venezuelan President Hugo Chavez sharply criticized the coalition's approach in remarks Saturday, Venezuelan state media reported.
The close friend and longtime ally of Gadhafi described the airstrikes as an imperialist military intervention and said "terrorists" had infiltrated groups of Libyan rebels.
"These groups kidnapped and massacred civilians and soldiers who supported and defended the sovereignty of Libya," he said.
CNN's Reza Sayah, Arwa Damon and Nic Robertson contributed to this report.