Tunisia has freed a United Nations expert monitoring sanctions against neighboring Libya who was held for nearly two months on suspicion of espionage.

The U.N. office in Tunis confirmed Wednesday that Moncef Kartas was released Tuesday on a provisional basis pending further investigation and is doing "relatively well."

Tunisian anti-terrorism officials have questioned Kartas' use of a special phone to track air traffic, and said the case concerns his personal activities and not his work for the U.N.

Tunis-based U.N. coordinator Diego Zorrilla told The Associated Press that Kartas' activities were connected to his U.N. mandate. He said Kartas should be protected by diplomatic immunity even though he has Tunisian citizenship, and that the U.N. wants his seized computer and telephone returned.

Kartas' lawyers say there's no proof of wrongdoing.