At least seven students and two teachers were killed in an attack on a public school by Boko Haram insurgents in Nigeria's northeastern city of Damaturu, the military said on Monday.

The insurgents attacked Government Secondary School (GSS) in Damaturu, capital of Yobe State under a state of emergency, at 9: 15 p.m. local time on Sunday, according to Lieutenant Lazarus Eli, spokesman of the military-led Joint Task Force (JTF).

"They opened fire and killed seven students while three were injured," the military said, adding that the gunmen also headed for the teachers' quarters and killed two of them.

Lt Eli said the Boko Haram fighters attempted to target the JTF at a checkpoint in the state capital. Three of the insurgents were killed while three soldiers were injured in the exchange of fire.

The spokesman said three of the insurgents were arrested by the JTF and put in its custody.

The chief medical officer of the Damaturu Specialists' Hospital, Salem M Umar, confirmed that eleven corpses were brought there, including seven students of the GSS Damaturu, two teachers of the school and two others identified as suspects of the Boko Haram military sect.

In addition, six students sustained various degrees of injuries. They were brought to the hospital and "are currently receiving treatment," the officer said.

Yobe State is one of the strongholds of Boko Haram, which launched an uprising in the West African country in 2009.

More than 1,500 people including women and children have been killed in attacks by the Boko Haram members.