A United Nations arms expert held in Tunisia since late March on espionage charges was released Tuesday on bail, the prosecution service said. Moncef Kartas is a member of the UN panel of experts investigating allegations of violations of an arms embargo and other sanctions imposed on Libya. The Tunisian-German dual national was detained on arrival in Tunis on March 26. “The indictment division has decided to release Moncef Kartas on bail,” prosecution spokesman Sofiene Sliti said. But Kartas was still being prosecuted for the “unofficial collection of information related to terrorism, which constitutes a dangerous crime,” he told AFP. The investigation had uncovered equipment used to control civil and military air traffic and whose use “requires authorization,” he added. Kartas’s defense team has said the charges are linked to the arms expert’s possession of a device allowing him to have access to data on flights of civil and commercial aircraft. The device, an RTL-SDR, was used “only for monitoring air traffic to Libya, in order to identify flights that could be linked to violations of the arms embargo,” said his lawyer, Sarah Zaafrani. Last week, the United Nations rejected Tunisia’s reasons for Kartas’s arrest and demanded charges be dropped and his immediate release. It argued that, as a UN employee, Kartas was subject to diplomatic immunity, but Tunisia challenged this. The UN panel investigating the alleged sanctions breaches has reported that arms and ammunition deliveries still reach warring parties in Libya — with the involvement of member states — despite the embargo. Libya, which borders Tunisia, has seen an uptick in violence since military strongman Khalifa Haftar launched an offensive on April 4 to take the capital Tripoli from the UN-recognized government. An arms embargo has been in force since Libya’s 2011 revolt that toppled its longtime ruler Muammar Qaddafi.