ISLAMABAD: Pakistan’s military on Thursday said it had killed 21 militants in airstrikes in a restive tribal district near the Afghan border, a region where it has been battling militant groups for more than a decade.

The attacks took place early morning in the Tirah valley of Khyber district, where the Taleban and another banned militant group, Lashkar-e-Islam, have taken refuge, the military said in a statement.

Pakistan has been battling militant groups in its semi-autonomous tribal belt since 2004 after its army entered the region to search for Al-Qaeda fighters that had fled across the border following the US-led invasion of Afghanistan.

In June, the army began an operation in the North Waziristan agency after a bloody raid on Karachi Airport ended faltering peace talks between the government and militants.

North Waziristan is a major base for the Tehreek-e-Taleban Pakistan (TTP), which began it’s campaign against the state in 2007.

The United States has long called for action against militant groups in North Waziristan who have used the area as a staging post for attacks against NATO forces in neighboring Afghanistan.

Pakistan’s army says it has killed more than a thousand militants and lost 86 soldiers since the start of the operation.

But the toll and identity of those killed is difficult to verify because journalists do not have regular access to the conflict zones.