Several residents in Tripoli were lightly wounded in the clashes which began Sunday night and spread across several neighborhoods.
Fighters from rival militias - the Al-Raada Force and the 444 Brigade, both of which are loyal to interim Prime Minister Abdulhamid Dbeibah's Tripoli-based government - clashed after a member of the 444 Brigade was arrested.
Libyan television and online media showed videos of the fighting posted online by social media users.
An elderly man "was injured in the arm by shrapnel as he fled his home in Ain Zara by car," the Tripoli Rescue Service said on its Facebook page, also condemning damage to ambulances during the gun battles.
On Sunday, armored vehicles and fighters were seen deploying in Jrabra Street, a busy commercial area in the capital's east, and the central Ras Hassan residential district.
After a lull in the fighting, heavy and light weapons fire was heard, along with ambulance sirens, in the eastern suburbs of Ain Zara and Fornaj until 0100 GMT Monday, according to an AFP correspondent.
The University of Tripoli said Monday it was forced to "close its doors" and suspend exams as a security measure.
The fighting was reportedly halted after the intervention of another armed group that is responsible for security, the Stabilization Support Agency.
The latest Tripoli fighting comes after drone strikes ordered by Dbeibah's government near the western city of Zawiya, claimed to be on targets connected to fuel and drug smuggling and people trafficking.
On Sunday, drone strikes killed at least two people and hospitalized the nephew of legislator Ali Bouzribah, from the rival eastern parliament, whose home had reportedly been hit in strikes three days earlier.
Libya is split between Dbeibah's U.N.-backed government in the west and another in the east backed by military strongman Khalifa Haftar.
Last August, 32 people were killed and 159 wounded in Tripoli when groups supporting the Haftar-backed government fought with Dbeiba's forces.