Mauritania has extradited Muammar Gaddafi's former spy chief Abdullah al-Senussi to Libya.
Mr Senussi was captured in the West African state in March, triggering a tug of war between Libya, France and the International Criminal Court for his extradition.
An official in Libya said Mr Senussi had arrived in the country and was in government custody.
A high-level Libyan delegation, including the justice minister and army chief of staff, was in Mauritania yesterday where it held meetings with Mauritanian authorities.
It was not clear if there was a court decision sanctioning the extradition.
A spokesman for the ICC, which has wanted to try Mr Senussi on charges of crimes against humanity, including murder and persecution, said it had received no information about a handover to Libyan authorities in Tripoli.
Mr Senussi was arrested six months ago after arriving with a falsified Malian passport on a flight into the Mauritanian capital Nouakchott from Morocco.
Mauritania's original plan was to put him on trial for illegal entry, a move that threatened to delay efforts to have him face international justice.
In its warrant for Mr Senussi's arrest, The Hague-based ICC said he had used his position of command to have attacks carried out against opponents of Gaddafi.
France has wanted to try Mr Senussi in connection with a 1989 airliner bombing over Niger in which 54 of its nationals died.
He has also been linked to the 1988 bombing over Lockerbie, Scotland of an American PanAm jet that killed 270 people.
Diplomatic sources have said the US was keen to question him about that attack.
Gaddafi's son, Saif al-Islam, is to go on trial in Libya this month in what would be the most high-profile prosecution of a figure from the late dictator's 42 years in power.
Libya's new rulers, who aim to draw up a democratic constitution, are keen to try Gaddafi's family members and loyalists at home.
However, human rights activists worry that a weak central government and a relative lack of rule of law mean legal proceedings will not meet international standards.
Saif al-Islam is also wanted by the ICC for crimes against humanity during the uprising that brought down his father.
