On Thursday night, militants fired a number of RPGs at the channel's headquarters, causing partial damage to the building, the employee, requesting anonymity, told The Anadolu Agency.
Al-Nabaa, which is affiliated with the Islamist "Dawn of Libya" militia umbrella group, has continued to broadcast despite having been targeted by militants more than once in recent months.
No group has yet claimed responsibility for the attack.
However, Islamist groups blame forces loyal to former army general Khalifa Haftar – who currently enjoys the backing of Libya's Tobruk-based government – for previous attacks on the channel's HQ.
Libya has remained dogged by political instability since the 2011 ouster and death of long-ruling strongman Muammar Gaddafi.
In the more than three years since, rival militias have frequently locked horns, often bringing violence to the country's main cities, especially Benghazi and capital Tripoli.
The sharp political divisions have led to the establishment of two rival seats of government, each of which has its own institutions.
Two assemblies currently vie for legislative authority: a recently-elected House of Representatives, and the General National Congress, which – even though its mandate ended last summer – continues to convene in Tripoli.
The two parliaments support two rival governments, which are respectively headquartered in the two cities.
International rights organizations, including Reporters without Borders, have previously expressed concerns regarding the targeting of media outlets in Libya.