Six medical workers that were held hostage by unknown men for nearly two weeks in Libya have been released, a leading human rights group said on Thursday.

Human Rights Watch said in a statement that the four physicians, a nurse and an anesthetic technician were released on Wednesday. Their nationalities were not immediately made available.

The organization said the abducted medical workers had been used as "bargaining chips for the release of an imprisoned man." Izzedine al-Wahishi, who is currently being held in the capital, Tripoli.

Libya has been beset by heightened violence since April, as forces loyal to General Khalifa Haftar, holding eastern Libya, attempt to take over Tripoli from GNA forces allied to UN-recognized Prime Minister Fayez al-Sarra.

The North African country has been dogged by violence since 2011, following the ouster and death of former president Muammar Gaddafi.

The war has killed thousands and displaced millions as militant groups and human trafficking cells seek to impose their command in various regions across the country.

The UN has led calls for dialogue between the warring factions in order to stop the war and put the country on a recovery path.

Abductions are common in Libya, where the two warring factions rely on armed militias.