One of Libya's most senior energy officials went missing on Thursday, family members have told the BBC.
Opec representative Samir Salem Kamal disappeared after he left his place of work in central Tripoli at around 15:00 local time, his relatives said.
There has been no official statement on Mr Kamal's whereabouts from the authorities running the Libyan capital.
Competing militias have been ruling the country since the overthrow of Col Muammar Gaddafi in 2011.
Officials representing the militia ruling Tripoli have allegedly told a family member that they know the location of Mr Kamal and are dealing with the matter.
But relatives, who asked not to be identified, told the BBC's Rana Jawad that they don't know who to turn to.
They say they have reached out to numerous groups to discover his whereabouts but most denied any knowledge of the matter.
"Some are telling us he is alright but at the same time denying they know where he is," said one.
"We have contacted all groups and officials and they deny they have him."
Opec is a 12-member organisation of oil producing nations.
Mr Kamal had been Libya's representative to the organisation for two years, and was also a senior manager at the planning and training department in Libya's Ministry of Oil.
The country has been in a state of growing chaos and conflict in recent months.
Following battles in Tripoli last summer, an alliance of armed groups took control of the city and installed a rival government that is not recognised by the international community.
The internationally-recognised government and elected parliament had to move to the east of the country in 2014.
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