Spokesman for the health ministry of the Government of National Accord has confirmed the air strike. At the time of the strike the cadets were gathered on a parade ground before going to their dormitories.
The military school is in al-Hadba al-Khadra, a residential sector of the Libyan capital.
The southern part of Tripoli has seen fierce fighting since last April, when military strongman Khalifa Haftar began an offensive against the GNA.
Libya was plunged into chaos with the toppling and killing of longtime dictator Moamer Kadhafi in a 2011 NATO-backed uprising. It has since become divided between the GNA and rival authorities based in the country’s east.