A number of U.S. federal agencies undertook a program at Groom Lake to evaluate the MiG-17 to help fight the Vietnam War, as the kill ratio against North Vietnamese MiG-17s and MiG-21s was only 2:1. The program was code-named HAVE DRILL (see also Have Doughnut), involving trials of two ex-Syrian MiG-17F Frescos, acquired and provided by Israel, over the skies of Groom Lake. These aircraft were given USAF designations and fake serial numbers so that they may be identified in DOD standard flight logs.