 Complete the following phrase:  Croatia acquired three MiG-21s in 1992 through defections by Croatian pilots serving with the JNA, two of which were lost in subsequent actions  one to Serbian air defenses, the other a friendly fire accident. In 1993, Croatia purchased about 40 MiG-21s in violation of an arms embargo, but only about 20 of these entered service, while the rest were used for spare parts. Croatia used them alongside the sole remaining defector for ground attack missions in operations 