Hours after Libyan protesters flushed out the Islamic militia from their stronghold Benghazi, two other militias are also to flee Derna.
The eastern city was a strong base for Islamic militant groups Abu Slim Brigade and Ansar al-Sharia.
The groups have announced that they would be disbanding following the recent protests by Libyan activists and government forces.
"The militia in Derna saw what happened last night and they decided: we will not kill our brothers. So they disbanded. They said they no longer exist as militias in Derna. They will go home and leave security to the interior ministry and army," Siraj Shennib, a linguistics professor who participated in the protests, told Reuters.
Before leaving the public buildings, a brief confrontation between protesters and militiamen was reported but it soon fizzled out when militants decided to vacate the region and not use force against the protesters.
"The people started coming because it has reached the limit. They are saying: we've had enough," he said. "It was a very peaceful operation. We are happy and we appreciate the effort the militias have done to save people from conflict."
Reports suggest that Derna was under constant watch by the protesters over the last two weeks before the demonstrations broke out. Derna was believed to be a prominent recruitment centre for Islamic militants where they were trained to carry out attacks in various countries. However, others contest this view.
The Islamic militia and the Libyan people became hostile to each other over the recent attack on the US consulate in Benghazi which was thought to be by Ansar al-Sharia. US ambassador to Libya Chris Stevens was among those killed in the attack.
At least 11 people were killed during the conflict when Ansar al-Sharia's compounds were stormed and close to 60 people were wounded.
Soon after evicting the militants, the protesters stormed pro-government buildings in the region mistaking them for militant-occupied places.