Some 200 gunmen have surrounded Libya's Foreign Ministry and demanded the government hire former fighters who helped overthrow the Gaddafi regime.
Armed men also stormed the Interior Ministry in Tripoli and a state-owned television station causing employees and security personnel to flee the building.
The men allege the ministry has not paid their salaries and that many supporters of the old regime are still holding senior positions in the Libyan government.
Libya's prime minister, Ali Zidan, has warned the country is facing a perilous security situation two years after the civil war that left many thousands dead.
Gunmen who stormed the al Wataniya TV channel, forcing employees out and live shows to be taken off air, demanded the removal of what they claimed were Gaddafi-era officials from the station.
The station was temporarily shut down recently when employees protested against armed militias providing security for the building instead of regular forces.
Mr Zidan told reporters in Tripoli that the situation could weaken Libya's standing in the international community.
"If the situation persists, it will give Libya a bad reputation and lead to foreign companies pulling out and embassies closing down," he warned.
Mr Zidan was himself besieged in his office last month by militiamen over remarks he made threatening to summon outside help to confront the armed groups.