Human traffickers in Libya reportedly killed more than a dozen people and wounded many others after a group of migrants being held captive attempted to escape.

The incident happened on Wednesday, May 23 in Bani Walid, approximately 180 kilometres southeast of the capital Tripoli, UNHCR spokesperson William Spindler said in Geneva on Friday.  

According to the survivors, people were shot while trying to escape and during attempts to recapture them.

The survivors spoke of torture abuse and exploitation at the hands of traffickers - some being held in captivity for up to three years. Some 200 Eritreans, Ethiopians and Somalis were being held captive.

The local Libyan authorities have transferred 140 people who managed to escape from the traffickers to an official detention centre in Gaser Ben Gashir, 28 kilometres south of Tripoli.

In Gaser Ben Gashir, the UNHCR has been distributing relief items, providing psychosocial support and undertaking protection screening to identify and register those in need of international protection.

Following this, UNHCR has identified a large number of unaccompanied children among the group. The UN refugee agency believes many refugees and migrants may still be hiding or in captivity in or near Bani Walid.

"This latest deadly incident demonstrates, once again, the huge challenge of providing protection to refugees in Libya, where many people fleeing war and persecution fall prey to criminal networks who exploit and abuse them or later often perish at sea while searching for safety in Europe," UNHCR said.

"UNHCR advocates for legal pathways for refugees to travel safely. We continue to call on resettlement countries and the international community to step forward, open more resettlement places and identify ways to protect vulnerable refugees in Libya, and beyond, who need international protection."