Forces loyal to Libya's late leader Moammar Gadhafi launched a series of attacks on Monday across several cities, killing seven fighters who helped topple the former regime, officials and residents said.
The violence comes as Libya's new leaders struggle to stamp out lingering resistance from pro-Gadhafi forces and try to unify a deeply fractured country after eight months of civil war and more than 40 years of authoritarian rule.
The attacks were spread out and took place in the western city of Bani Walid, the capital Tripoli and the eastern city of Benghazi, the city where the uprising against Gadhafi started nearly a year ago. It is not clear if the attacks were coordinated.
Violence broke out first in Bani Walid, where pro-Gadhafi fighters have long tormented Libya's revolutionaries.
Mahmoud al-Warfali, a spokesman for the revolutionary brigade in Bani Walid, said at least four of his fighters were killed in the western city, which was one of the last former regime strongholds to fall to revolutionary command.
He said up to 150 pro-Gadhafi fighters were engaged in the street battle, using rocket-propelled grenades and AK-47s. He said they managed to raise the green Libyan flag of Gadhafi's regime at the northern gate of the town.
"These are Gadhafi remnants who tried to take over the city," al-Warfali said. "They have tried to do this before and take over the interim government's office, but thank God we have been able to fight them off."
Hours later, three fighters were killed late Monday by pro-Gadhafi forces in Benghazi, field commander Abdel-Basit Haroun said. The city served as the hub for revolutionary leaders during the civil war.
Abdel-Rahman al-Soghayar, a commander from the new regime in Tripoli, said shooting also took place in several neighborhoods of the capital Monday evening, forcing people to remain indoors and stores to close early. He blamed the gunfire on "sleeper cells" loyal to Gadhafi who he said are attempting to take advantage of the fighting in Bani Walid. There was no word of casualties.
The bold attacks are the latest breakdown in security, three months after Gadhafi's capture and killing. Protests have surged in recent weeks, with people demanding that the interim leaders deliver on promises of transparency and compensation for those injured in the civil war.
The new government's promises to deliver justice for those killed in the uprising has been usurped in some areas by revolutionary fighters taking retribution on their own.
Bani Walid resident Moussa al-Warfali said the clashes erupted after revolutionary forces arrested a Gadhafi loyalist, whose angry comrades launched an attack to free him.
The fighting originally was centered on the revolutionary brigade's base, then spread to other parts of the town.
The clashes were considered serious enough that dozens of revolutionary fighters from Tripoli have been dispatched to Bani Walid to help, brigade commander Saddam Abdel-Zein said.
There were also reports of shooting in the western Nafusa mountains, according to al-Soghayar, who was in touch with fellow fighters there. No further details were available.
The outbreak of violence prompted revolutionary fighters as far as the western city of Misrata to declare a high alert, setting up check points and securing entrance points to the city, according to Misrata's revolutionary brigade spokesman, Walid Khashif.
After the fall of Tripoli to anti-Gadhafi fighters in August, loyalists of the ousted regime took refuge in towns such as Bani Walid and held off revolutionary forces for weeks, using the surrounding mountains and valleys to pick off revolutionary forces.
Even after Gadhafi's capture and killing in October, the city and its surrounding region have troubled Libya's new leaders.
In November, 15 soldiers were killed in an ambush by Gadhafi loyalists just outside the town. Revolutionary fighters in Bani Walid have complained that the country's interim government has done little to help secure the city.
Batrawy reported from Cairo.