BENGHAZI - Thousands of Libyans marched in Benghazi on Friday in support of democracy and against the Islamist militias that Washington blames for an attack on the US consulate last week that killed four Americans including the ambassador.The "Rescue Benghazi day" demonstration called for the government to disband armed groups that have refused to give up their weapons since the NATO-backed revolution that toppled Muammar Gaddafi last year. Marchers headed for a main square where a much smaller counter demonstration of hundreds of supporters of hardline Islamist group Ansar al-Sharia were waiting."It's obvious that this protest is against the militias. All of them should join the army or security forces as individuals, not as groups," medical student Ahmed Sanallah, 27, said. "Without that there will be no prosperity and no success for the new Libya."The late afternoon demonstration had a cheerful atmosphere as families marched with small children on their shoulders.Fighter jets and helicopters roared overhead in a show of official support for the demonstration, which has been enthusiastically promoted by the city's authorities."Those military battalions that want to impose their ideology on the people of Libya will be confronted," Saleh Gaouda, a member of new ruling national congress, said."This city wants to go back to stability and participate in building the state."In a sign of the cheerful atmosphere, one car had a giant cardboard model of Benghazi's landmark lighthouse strapped to the roof. As the sun set and the crowd began to disperse, someone shot fireworks into the air.Defend BenghaziAlthough the main demands of the marchers did not mention the attack on the US consulate, it seems to have provided a strong impetus for the authorities to rally support behind the country's weak government.US ambassador Christopher Stevens was well liked in Libya, and many people who were angered by an anti-Islamic film made in the United States consider the attack on the embassy to have been excessive. Some placards in English, intended for international news cameras, read: "We demand justice for Stevens" and "Libya lost a friend"."I am out today to defend Benghazi. Killing the ambassador is a completely separate thing," 26-year-old Amjad Mohammed Hassan, a network engineer, said. "I don't give a damn about the killing of the ambassador because the Americans offended the Prophet. I am just here for Benghazi."Benghazi, 1,000 km (600 miles) from Tripoli across largely empty desert, is controlled by various armed groups, including some comprised of Islamists who openly proclaim their hostility to democratic government and the West.Some of these have been identified by local people as being among those who were at the consulate protest last week. US officials have described the violence as a "terrorist attack".One group linked to the attack is Ansar al-Sharia, which has denied involvement in the violence.Abu Al-Qaa, a demonstrator at the Ansar al-Sharia counter demonstration, said Stevens "was preparing for the entry of American troops into Libya"."The will of the Prophet was to expel infidels from Muslim lands so that Muslims prevail. Terrorizing your enemy is one of Islam's tenets."He said he had fought against American troops in Iraq where he was arrested and sent back to Gaddafi's Libya and jailed for three years.One banner at that demonstration read: "Day to rescue Benghazi or day to rescue America?"In southern Libya, at least six people were killed and 12 injured in clashes between security forces and a local group, a security official and a resident said on Friday.Security forces were sent to the town of Brak, 700 km (400 miles) south of Tripoli, on Wednesday to stop a group broadcasting songs about Gaddafi on the radio, the official said. The security forces, made up of former rebel fighters, came under attack upon arrival.