The French government is investigating a senior French military officer working at an Italy-based NATO facility, monitoring the situation in Libya and the Sahara, for passing sensitive information to Russian.

Minister of the French Armies, Florence Parly told Europe 1 radio "What I can confirm is that a senior officer is facing legal proceedings for a security breach," but gave no further details.

The lieutenant-colonel officer worked at a command center near Italian Naples, established at the end of 2017. Around 100 people work in the center which task is to observe the Mediterranean region, including the Middle East, the Greater Sahara, and Libya.

The officer had reportedly passed on "ultra-sensitive" information to Russian intelligence services and was seen with a man identified to be a Russian intelligence agent.

The top officer was arrested on August 21 by the French intelligence agency DGSI as he was preparing to leave for Italy at the end of his holidays in France, according to France's Europe 1 radio, noting that he is being held at a prison in Paris.