Gunmen have attacked a military-run secondary school near Kano in northern Nigeria, killing four air force personnel and injuring two more, reported the BBC.
Northern Nigeria has been suffering violence from Islamist militants, but Kano has not been targeted recently.
Kano residents reported they heard gunshots from the school and said the gunfire lasted 30 minutes, according to AFP.
More from GlobalPost: Nigeria braces for more extremist violence
There has been no claim of responsibility for Thursday's incident but it is widely susptected to be the work of the Islamist extremist group Boko Haram, which has carried out a wave of bombings and killings in Nigeria in recent years.
Boko Haram has been blamed for scores of attacks, mostly in northeastern Nigeria, and the group also claimed responsibility for the August suicide bombing of the United Nations office building in the capital Abuja that killed at least 24 people.
There has been intense speculation over whether Boko Haram has formed links with outside Islamic extremists, especially the North African branch of Al Qaeda.
Boko Haram is believed to have a number of factions with varying aims. The group launched an uprising in 2009 that was put down by a military assault which left some 800 dead. The group was then dormant for about a year before emerging with a series of assassinations.
Bomb blasts have since become frequent and have grown in sophistication.