In the latest sign that a rebel advance on Tripoli may become slower and more chaotic, forces loyal to Libyan leader Moammar Gaddafi on Wednesday recaptured a town in the mountains south of the capital that was taken with great fanfare by rebels one week ago.

Early Wednesday, government troops surged from their positions in the fortified city of Gharyan and quickly retook the town of Qawalish in the barren pasturelands of the western mountains.

The Libyan government troops easily overran lightly defended rebel checkpoints and began roaring down the two-lane highway toward the main rebel stronghold of Zintan, creating a few hours of anxiety.

“Today, we are in a very serious situation,” said Edweb Musa, an elderly fighter.

“Our people were asleep on the job,” said Salem Mufti, a rebel fighter. “It was a surprise that Gaddafi soldiers came so fast.”

The successful advance on the embattled town of Qawalish, however brief and insignificant in the larger civil war, shows that the Gaddafi army is still obeying orders and is capable of offensive action.

“The attack was quick. The Gaddafi soldiers moved on the blacktop with heavy equipment,” said Col. Muhammad Khabasha, a rebel leader here who served for 34 years in the Libyan army until he defected to the rebel side in February shortly after the uprising began in the oil-rich North African state.

Khabasha and other leaders did not seem overly concerned that they had lost Qawalish. “We will take it back from them very quickly, maybe today, maybe tomorrow, don’t you worry,” Col. Juma Ibrahim, one of the rebel commanders, said on his way to lunch.

True to his word, by late afternoon, hundreds of pickup trucks filled with rebel fighters — many dressed in T-shirts, flip-flops and blue jeans, some without rifles, all without helmets or body armor — were rushing to close the breach and push the Gaddafi forces back into Qawalish.

At the nearby front line, as rockets fired from rebel positions in the vague direction of the Gaddafi troops, rebel trucks careered down the highway, shouting praises to Allah and firing weapons in the air.

Although neither side seemed especially professional at war, the rebels in the western mountain region south of Tripoli have been praised by NATO planners as the best hope to cut off the capital by taking major towns along the highways that serve as supply lines for the Libyan regime, bringing food and fuel from the west and guns, ammunition and mercenaries from the south.

Although the fighting in eastern Libya has stalled, the rebels in the western mountains have moved effectively, taking town after town. That push may be slowing. Rebel commanders have said that they are fighting without weapons and adequate fuel, with untrained troops and little help from NATO.

“If NATO gave me a helicopter, I would be in Tripoli in three days,” said rebel commander Col. Moktar Lakder, who served in the Libyan army for 25 years before retiring in 1998.

As the sun set on a day of advance and retreat, the rebels were trying to retake Qawalish — again.

On Wednesday, Human Rights Watch said in a report based on interviews with local fighters and residents that the rebels had looted shops and clinics and torched the homes of suspected government supporters in some of the towns they had seized in the region, the Associated Press reported. The spokesman for the rebel council in Benghazi said that if there was evidence of that, those involved would be brought to justice.