Gunmen opened fire at a primary school in the northern Nigerian city of Kano on Tuesday, injuring four teachers before fleeing on a stolen motorcycle, police said.
There were indications that theft was the motive for the attack, but Islamist group Boko Haram has razed several schools in the region as part of an insurgency that has killed hundreds since 2009.
Just before classes were due to begin, two armed men stormed a state-run primary school in the Danmaliki suburb of Kano, the largest city in mainly Muslim northern Nigeria.
"The gunmen shot and injured four teachers including the headmaster and fled but we have opened an investigation into the attack and have deployed policemen...for a manhunt," Kano state Police Commissioner Musa Daura said.
The assailants forced several people to lie face down on the ground, robbing mobile phones and cash before they started shooting, the police chief said.
The gunmen fled on a motorbike that belonged to one of the victims.
The name Boko Haram roughly translates as "Western education is forbidden" and the radical group has burned schools in several parts of the north, but such incidents have typically occurred after hours when schools are empty.
Daura declined to comment on the suspected motive for the shooting.
Boko Haram has been accused of scores of attacks in Kano, but as its prominence has grown it has also been blamed for violence carried out by local gangs.