In a striking reversal of fortune, "people power" demonstrators marched on bases in Benghazi belonging to the increasingly powerful Ansar al-Sharia, driving it out of its strongholds.
They had the support of members of the regular police and army, whose absence from the streets was the target of an earlier protest by tens of thousands of city residents.
The 30,000-strong protest was called on Friday night out of anger at the death of the US ambassador, Chris Stevens, 12 days ago, and to demand that the country's newly elected authorities reclaim Benghazi from heavily armed militias.
Some of the crowd in the early hours of yesterday (Saturday) then turned on another Islamist militia, the Rafallah al-Sehati Battalion, stationed in the west of the city. But its leaders claim to be allied with pro-government forces, and fought back at what they said were "criminals and drunks".
In the fighting, at least 11 people died and scores were wounded, according to staff at two hospitals to which the injured were taken. One medical official claimed six bodies showed signs of having been subject to "execution".
The events divided Benghazi, the eastern Libyan city that considers itself the cradle of the revolution that overthrew Col Muammar Gaddafi but which is also far more devoted to conservative Islam than the more cosmopolitan capital, Tripoli.
"Ansar al-Sharia is finished now," said Abu Bakr Faraj, whose leg was broken when he was hit by a car full of what he said were Kalashnikov--toting Ansar al-Sharia supporters fleeing attack. "We hope they don't come back."
The killing of Stevens and three other American staff at the Benghazi consulate on September 11 has presented Libya with its biggest crisis since the death of Gaddafi, crystallising fears about the weakness of the government and the rise of Islamist and other militias.
Century Fox Report: Tension rises as Anti-US protests continue in Libya
Conspiracy theories, always prevalent in Libya, have been exacerbated by competing stories from the authorities in both Washington and Tripoli about the original attack. Washington at first insisted it was a protest connected to the anti-Islam film circulating the internet that got out of hand, but now accepts it was "terrorist" in nature, possibly carried out after communication with al-Qaeda.
Witnesses said they saw no demonstrators near the consulate before it was hit from three sides by scores of men wielding automatic rifles and grenade launchers.
It has also become clear that at least 30 Americans were evacuated from a previously undisclosed "safe house" half a mile from the consulate, raising questions about the nature of their work. Officials briefed The Wall Street Journal that they included "officials and security personnel involved in sensitive government programmes".
The new prime minister, Mustafa Abushagur, elected on the day after the attack, was forced to divide his time last week between trying to appoint a new government and holding crisis talks with military and militia leaders.
The anger of the Rafallah al-Sehati Battalion at being attacked on Friday was compounded by the fact that its leaders had offered to negotiate a peaceful solution with Ansar al-Sharia, whose members they acknowledged had a role in Stevens's murder.
But the demonstrators demanded an absolute end to the power of the militias. They called themselves the "Rally to Save Benghazi", held up banners saying "We demand justice for Stevens" and chanted "Libya, Libya" and "No more al-Qaeda".
In a sign of their fear of resurgent violence the prime minister, the chief of army staff, Gen Yousef Mangoush, and the interior minister, Fawzi Abdel-Al - the very leaders in whose name the crowds claimed to be acting - issued statements condemning what had happened.
Libya's acting president, Mohammed Magarief, also called on the demonstrators to go home.
-- A Pakistani cabinet minister has personally offered a $100,000 (pounds 61,600) bounty for the murder of the American maker of the film that sparked angry protests throughout the Muslim world because it was deemed offensive to the Prophet Mohammed.
"Whomsoever can kill the blasphemer will be covered in dollar bills by me," the federal minister for railways, Ghulam Ahmed Bilour, said, after riots in Pakistan left 22 people dead and some 200 injured.
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Edited By Cen Fox Post Team
