Benghazi , Libya ( CNN ) -- Two Islamist militias have agreed to close their bases in the eastern Libyan city of Derna , state news and a source said Saturday . A third base will be shut on Sunday , said the source , who spoke on the condition of anonymity . The state-run LANA news agency said the militias , which it identified as Bou Salim Martyrs and Ansar al-Sharia , will also disband . The move comes after hundreds marched in the nearby city of Benghazi and took over the headquarters for Ansar al-Sharia . Individuals from the radical Islamist group are accused of having been involved in the attack last week that left four Americans dead . Protesters demanded an end to all security activities of armed groups operating outside the official command of the army or police . Mohamed al-Magariaf , president of Libya 's General National Congress , later told reporters that a joint security office would be established to bring together the army and the various brigades backed by the government . Militias outside that office will not be allowed to operate , he said . As militia members fled the headquarters in Benghazi , demonstrators torched a vehicle and took over the group 's building without firing a single shot . 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 . Some protesters also 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 there , but it was not clear who was responsible . At least four people were killed and 70 were injured in clashes at the Rufallah al-Sihati brigade headquarters , LANA reported . Al-Magariaf 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 . On the night of September 11 , U.S . Ambassador Chris 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 .
A third base will shut on Sunday , says a source . The move comes after protesters overtake an Libyan group 's HQ in Libya . 70 people are killed and At least four injured in clashes , state news reports .