The U.N. says it was informed that a Tunisian appeals court has decided to release Mocef Kartas, a U.N. expert monitoring sanctions against Libya, who was arrested following his arrival in Tunis on March 26.

U.N. spokesman Stephane Dujarric said Tuesday the U.N. is "very encouraged by this development" and is looking forward to confirmation of his actual release from detention. The U.N. is also seeking further information from the government including on the status of legal proceedings against Kartas, he said.

Kartas has dual German-Tunisian nationality, but the U.N. has insisted that he be freed because experts on U.N. missions have diplomatic immunity.

His family said he was being investigated for "allegedly possessing and disclosing intelligence information concerning national security to foreign governments."