The fighters were members of the group’s armed wing, Al-Quds Brigades, at a training camp near Rafah in the southern Gaza Strip. Medics confirmed the death toll.
An israeli army spokesman, contacted by AFP, said the air force carried out a raid on Gaza but declined to give further details.
An Al-Quds Brigades commander, Ahmed al-Sheikh Khalil, was among the fighters killed in the air strike, according to the Islamic Jihad. The group also pledged to “respond” to the raid.