Libya has requested the handover of Muammar Qaddafi's former intelligence chief, Abdullah al-Senussi, following his arrest in Mauritania.
A spokesman for Libya's ruling National Transitional Council, Mohammed al-Harizy, "insisted" that Senussi be extradited to Libya to face trial.
Senussi is also sought by the International Criminal Court (ICC) on charges of crimes against humanity.
France also wants to extradite him in connection with a 1989 bomb attack on a plane that killed 170 people.
Mauritania has said it wants to carry out its own investigation before considering any extradition requests.
Mauritania's officials said they arrested Senussi as he arrived at Nouakchott airport, after flying in from Morocco.
Senussi fled Libya last year as Qaddafi's regime crumbled.
With AFP, AP, and Reuters reporting