 The J-21 entered service with the JRV (Yugoslavian Air Force) on 31 December 1968, with very few, if any, remaining in service.According to some reports, France and Yugoslavia supported Mobutu's government during the First Congo War.Namely, Yugoslavia agreed to deliver three J-21 and a single G-2 aircraft, as well as four MiG-21PFMs, while three Mi-24s were purchased from Ukraine.