In this city 30 miles west of Tripoli, hundreds of people rejoiced in a central square on Sunday, waving the flag of free Libya and shouting the chants that foretold the downfall of governments in neighboring Tunisia and Egypt: “The people want to bring down the regime.”

Rebels, in control of the city, had reinforced its boundaries with informal barricades, and army units that had defected stood guard with rifles, six tanks and anti-aircraft guns mounted on the backs of trucks. In the central square here, a mosque was riddled with enormous holes, evidence of the government’s failed attempt to take back this city on Thursday. Nearby lay seven freshly dug graves belonging to protesters who had fallen in that siege, witnesses said…

Proving how close opposition control has come to the capital, where Col. Muammar el-Qaddafi maintains tight control, the confidence of the demonstrators in Zawiya was remarkable, all the more so because it was witnessed as part of the official tour for international journalists that Col. Qaddafi’s government organized. The public relations effort, apparently intended to show a stable Libya to the outside world, appeared to backfire, as a tour of Tripoli had on Saturday…

Since his own defection to the opposition last week, the former justice minister, Mustafa Mohamed Abd al-Jalil, has been meeting with tribal leaders and military commanders who have also defected. In an interview earlier in the week, Mr. Jalil pledged he would head a caretaker government that would hold interim elections within three months, and said the opposition had no intention of organizing a breakaway state.