Story highlights Protesters ask troops to take control of an Islamist group's HQ, a general says

"I am sorry, America... This is the real Libya," a protester in Benghazi says

Hundreds take over the Ansar al-Sharia group's headquarters without firing a shot

That group is tied to an attack last week that left 4 Americans dead

Ten days after four Americans were killed in their Libyan city, hundreds marched in Benghazi and took over the headquarters of a radical Islamist group tied to the attack.

Thousands of protesters had taken to the street earlier Friday, loudly declaring that they -- and not those behind last week's deadly attack -- represent the real sentiments of the Libyan people.

"I am sorry, America," one man said. "This is the real Libya."

In the evening, an offshoot of several hundred people then headed toward the headquarters for Ansar al-Sharia, a loosely connected radical Islamist group.

As militia members fled, the protesters torched a vehicle and took over the group's building without firing a single shot. Some of those involved claimed to have freed at least 20 captives held inside, and expressed their intent to assume control over other Ansar al-Sharia buildings.

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Army General Naji al-Shuaibi said the citizens, whom he referred to as "revolutionaries of the February 17 uprising," later asked that the Ansar al-Sharia headquarters be handed over to the Libyan army.

"Indeed, we rushed here and we will now take it over," said the general. "There are also other places that we intend to take over (which belong to armed groups) if the revolutionaries and the people allow us to do so."

But some of the protesters gathered at locations that house forces loyal to the national authority, he said, including the headquarters of the Rufallah al-Sihati battalion. Gunfire could be heard at the headquarters, but it was not initially clear who was responsible.

Mohamed al-Magariaf, president of Libya's General National Congress, thanked the protesters for helping evict "armed groups. He also said the Rufallah al-Sihati brigade was actually "under the command of -- and committed to -- the national authority," the case appeared to be one of mistaken identity. Magariaf asked demonstrators to stop their activities and go home.

There was widespread speculation that anti-national authority groups capitalized on the euphoria after the takeover of the Ansar al-Sharia headquarters and pushed protesters to move toward locations under the control of the army and the police force.

On the night of September 11, U.S. Ambassador Christopher Stevens was one of four Americans slain after a group assaulted the U.S. Consulate in the eastern Libyan city.

Seen as the birthplace of the revolution that led to the death of longtime Libyan leader Moammar Gadhafi, Benghazi has in recent months been beset by security issues.

Initial reports indicated that, ahead of the consular attack, Ansar al-Sharia had organized a protest to decry an inflammatory film that mocks the Prophet Mohammed and also protest the United States, where the film was privately produced.

On Thursday, Libyan Prime Minister Mustafa Abushagur said eight detained in connection with that assault include members of Ansar al-Sharia, though he added that not all the attackers came from one specific group.

Responding to the report from Benghazi, U.S. Sen. John McCain applauded the citizens' efforts Friday and said it represented the true, freedom-loving Libya that he and other U.S. officials involved in the country knew.

"Somewhere Chris Stevens is smiling," the Arizona Republican said. "This is what we knew ... about Libya."