Media sources from Qasir Benghashir, southern Tripoli, said gunmen loyal to Khalifa Haftar's forces kidnapped the member of the High Council of State Mohammed Abu Gamja on Friday from his house, adding that his whereabouts are still unknown.
Haftar's forces have been launching arrests of people who oppose the advance on Tripoli since April 04.
They have also arrested several activists and citizens who oppose Tripoli offensive, including Saad Al-Fakhiri - the Head of the Oil Workers' Union.
The National Oil Corporation called on Haftar's forces to release Al-Fakhiri.
Meanwhile, Gharyan - which is under the control of Haftar's forces since April 04 - had seen arrests of anyone who opposes Haftar's grip on the city.
Bodies of nine of arrested persons in Gharyan were found in Chinese Buildings neighborhood in what appeared as an execution after torture.