The Libyan representative to the oil producers’ organisation Opec has been released, more than two weeks after being kidnapped.
Samir Salem Kamal had been seized after leaving work in the Libyan capital, Tripoli, on 15 January.
His family said he was in good health considering the situation, but shaken up by his ordeal.
They said the identities of his kidnappers – and their motives – remained unclear.
Mr Kamal has been Libya’s representative to Opec – a 12-member organisation of oil-producing nations – 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.
Competing militias have been ruling the country since the overthrow of Col Muammar Gaddafi in 2011.
After Mr Kamal’s disappearance, relatives said they had contacted numerous groups in an effort to discover his whereabouts but most denied any knowledge of the matter.
Then on Sunday morning, they received an anonymous phone call saying that he had been released and was on the motorway in Tripoli, the Libyan newspaper al-Wasat reported.
“He is well considering the situation; in good health, but a bit shaken up,” the family said in a statement.
“Unfortunately, the people responsible for his kidnapping are still unknown as are the reasons unclear.”
Mr Kamal’s son told the newspaper he was blindfolded and unable to identify his abductors.
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.