An UAE Air-Tractor AT-802 conducted an airstrike on besieged district of Ganfounda in Benghazi on Saturday leaving a civilian's house and foreign workers' residence in ruin.
Local sources said a man and his two daughters were killed while another daughter had suffered severe wounds. Other family members are still under the rubble.
One Chadian worker was also killed, the sources confirmed.
The United Arab Emirates has established a military base in east Libya to back Khalifa Haftar's self-proclaimed army in its ongoing war in Benghazi.
Amnesty International warned in October that life of hundreds of local and foreign civilians in Ganfouda is in danger following months of blockade and air bombing by Dignity Operation and its foreign allies.
Dignity Operation poured scorn on Amnesty International report and confirmed that airstrikes would continue to kill what it described as Ganfouda terrorists.