BENGHAZI, Libya — Government forces carried out a bloody siege of Zawiyah on Saturday, bombarding the rebel-held western city with mortar fire and deploying tanks in the streets and snipers on rooftops.
But even as it pressed its counterattack against a resistance that vowed to fight on, emboldened opposition forces in the east backed away from calls for international airstrikes and pledged to take the battle against Libyan leader Moammar Gadhafi to his stronghold in the capital, Tripoli, on their own.
The day's events suggested the bid to oust Gadhafi was developing into precisely what Western observers have feared: a potentially protracted civil war.
The violence in Zawiyah, a city vital to Libya's oil industry and where witnesses said dozens had been killed and hundreds wounded Saturday, offered a chilling glimpse into what could become an inconclusive and bruising conflict with an ever-mounting death toll.
By late Saturday, both the government and the opposition claimed control of Zawiyah. Though impossible to verify, witnesses described a "massacre" in the worst of a two-day siege that saw shells rain on neighborhoods and bullet-ridden bodies of fighters strewn in the streets of the city, just 27 miles west of Tripoli.
After striking the city Friday, loyalists reportedly led by Gadhafi's son Khamis dramatically escalated their attack Saturday. At 7 a.m. local time, tanks rolled into the city accompanied by heavy shelling and machine-gun assaults, with witnesses reporting great plumes of black smoke billowing from various neighborhoods. Yet within three hours, the rebels succeeded, witnesses said, in driving Gadhafi's forces out of the city's center after blowing up two tanks with hand-held rocket-propelled grenades.
Loyalist snipers took positions on rooftops, firing on the central square before pulling back to the city's perimeter. The shelling of the city, however, continued.
Rebels claimed to be inflicting heavy damage on their better-armed opponents, saying dozens of Gadhafi's fighters had been killed.
"It is a massacre, they are striking civilians, they are attacking us from all directions," Mohammed Ahmad, a 31-year-old doctor, said by phone during one of the attacks. Explosions and whizzing bullets could be heard around him as he spoke. "People are running around shouting, 'God is great!' You can hear the shooting everywhere. This is madness. Why is the international community not interfering?"