The UN mission in Libya said it was "gravely concerned" by reports of the "enforced disappearance" Wednesday of Siham Sergewa and the wounding of her husband during the assault.

It called for an investigation into the disappearance and for Sergewa's immediate release.

"UNSMIL stresses that silencing the voices of women in decision-making position will not be tolerated," it added.

Security services in Benghazi have not commented on the incident, which came a day after Sergewa spoke on pro-Haftar Al-Hadath television and called for "an end to the bloodshed".

She was referring to an offensive launched by Haftar in early April to wrest control of the capital Tripoli from forces loyal to the UN-recognised Government of National Accord (GNA).

Haftar backs a parallel administration based in Libya's east, which his forces control along with much of the country's south.

Sergewa had also condemned lawmakers for taking sides over the Tripoli offensive and further "dividing" themselves.

In early May, 42 deputies from the eastern administration boycotted the body over Haftar's assault on Tripoli.

In a statement Wednesday, the dissident lawmakers condemned the abduction of their colleague, calling on the Benghazi security services to "work for the release of Ms. Sergewa".

The GNA accused "militias in Benghazi" of having "abducted" Sergewa, calling the crime "a natural result of the absence of law" in areas under Haftar's control.

Nearly 1,100 people have been killed, 5,752 wounded and more than 100,000 displaced in Haftar's months-long campaign to wrest control of Tripoli from the GNA, according to the World Health Organization.