TRIPOLI, Libya -- A gunbattle erupted between revolutionary forces and Muammar Qaddafi supporters Friday in the heart of the Libyan capital for the first time since the longtime leader was ousted and forced into hiding.

Shouting "God is Great," anti-Qaddafi fighters converged on the Hay Nasr district of Tripoli's Abu Salim neighborhood in pickups mounted with weapons, setting up checkpoints and sealing off the area as heavy gunfire echoed through the streets.

Fighters at the scene said the shooting began after a group of armed men tried to raise the green flag that symbolizes Qaddafi's regime. There were conflicting details about how the shooting began.

Assem al-Bashir, a fighter with Tripoli's Eagle Brigade, said revolutionary forces suspected there were snipers in the surrounding high rises after spotting a man trying to raise the green flag.

Another fighter, Ahmad al-Warsly, from the Zintan brigade, said several Qaddafi supporters apparently planned a protest but drew fire because they were armed. They then fled and were pursued by revolutionary forces, prompting fierce street battles.

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Al-Warsly said one man carrying a gun was captured and identified as a suspect wanted for the killings of protesters in the nearby city of Zawiya.

"It seems like it was organized," he said. "They were planning to have a big demonstration, then the fight started."

The violence in the capital, which has been relatively calm since then-rebels seized control of the city in late August, underscored the difficulty Libya's new rulers face in restoring order as Qaddafi remains on the run.

He has issued several audio recordings from hiding trying to rally supporters against the North African nation's transitional leadership.

Revolutionary forces also are fighting remnants of the regime in Qaddafi's hometown of Sirte and the desert enclave of Bani Walid.