Pakistan military courts have sentenced seven "hardcore" militants to death over various attacks on security forces that left dozens dead, including civilians, the country's army chief said Friday.

A statement issued by the military's Inter Services Public Relations (ISPR) gave few details of the assaults each suspect was convicted of, but said that in total the attacks caused the deaths of 85 people and injured 109 others.

Referring to the detainees as "hardcore terrorists", the statement said they were "involved in heinous offences related to terrorism, including killing of innocent civilians, attacking Law Enforcement Agencies and Armed Forces of Pakistan".

It did not specify which organisations the suspects were thought to belong to.

Pakistan's military courts allow the army to try civilians on terror charges in secret, despite strong criticism from rights groups.

They were established in the wake of a December 2014 Taliban massacre at an army-run school in Peshawar that killed over 150 people, mostly school children.

Following that attack the government lifted the moratorium on the death penalty. Scores of militants have since been condemned to death.