Moammar Gaddafi’s forces pushed farther eastward Saturday toward a strategic port city, pounding terrain with airstrikes and rockets and delivering a setback for Libya’s rebels.

By Saturday night, the front line had been pushed back to the city of Brega, 77 miles east of Ras Lanuf, which only seven days ago was seized by rebel forces, who vowed to march on to the capital, Tripoli. The swift gains by Gaddafi’s forces underscored their superior military capabilities against the ragtag rebel force, which lacks firepower, organization and training.

Gaddafi’s forces appear to be systematically targeting each rebel-controlled city along the Mediterranean coast, pushing closer to Benghazi, where a provisional leadership to replace Gaddafi’s regime has been established.

In Ras Lanuf, which fell to government forces Friday night, there were signs everywhere of the rebels’ hasty retreat, including burned-out pickup trucks mounted with antiaircraft guns and ammunition boxes scattered along the road leading into the city.

A plume of dense black smoke from a burning storage tank at the nearby refinery, Libya’s largest, hung over the city and drifted along the coastal highway for miles. Government officials said rebels had taken shelter in the refinery and sabotaged the tank as they fled, though that could not be independently confirmed.

The seaside town of white, low-rise apartment buildings was deserted, save for a few dozen Gaddafi militiamen who circled the streets in trucks, honking horns and chanting pro-Gaddafi slogans, apparently for the benefit of the journalists bused there by the regime to demonstrate that the town is in government hands.

Haj Omar Ibrahim, 57, a security guard at the hospital here and seemingly the only resident to have remained behind, said the town’s other inhabitants, including the hospital’s staff members and patients, fled toward Benghazi as Gaddafi forces closed in.

Senior officials of the National Transitional Council, the provisional leadership in eastern Libya, conceded that they had faced setbacks but denied losing Ras Lanuf. They accused Gaddafi of waging a disinformation campaign.

“It is psychological warfare to dampen the morale of the people,” said Abdul Hafidh Ghoga, the council’s vice chairman. “Nobody should believe it.”

Omar Hariri, a top opposition military official, said rebel capabilities were “unequal” to those of Gaddafi’s forces, especially because the rebels lacked an air force. Like senior National Transitional Council officials, he called for the imposition of a no-fly zone, saying that rebel forces were “organized and determined to fight.”

“We are powerful, and we know how to fight. We know how to win,” Hariri told reporters in Benghazi.

Meanwhile, an al-Jazeera cameraman was killed Saturday in an ambush near Benghazi, the Associated Press reported. Ali Hassan al-Jaber, a Qatari national, was the first journalist killed in the conflict, the news network said.

Raghavan reported from Benghazi, Libya.