PARIS, July 20 (Reuters) - A French Mirage 2000 jet fighter crashed in northern Mali on Tuesday due to a technical problem, the French military said. The two pilots involved were safe, armed forces spokesman Colonel Pascal Ianni said. The crash occurred in Hombori region. The military will open an investigation into the reasons for the crash but militant groups were not behind the incident, he said. "Terrorist groups are not the cause of the problem", Ianni said.