Tripoli continues to be shaken by more than a week of clashes between rival groups.
It is the latest episode of chaos in the North African country since Muammar Gaddafi was toppled in 2011.
Footage shot on Wednesday showed one armed faction, the Bab Tajoura Brigade, operating in the west of the Libyan city.
There is no police or army or functioning state to enforce peace in a country ruled by armed groups who ignore authority and form flexible alliances.
Tripoli is formally controlled by the internationally recognised Government of National Accord, but armed groups working with it act with autonomy.
On Tuesday, the UN said rival parties have agreed to ceasefire.