BAGHDAD, July 22 (Xinhua) -- Fifteen Islamic State (IS) militants were killed on Sunday in an airstrike on an IS hideout in Iraq's eastern province of Diyala, provincial security source said.

Acting on intelligence tips, the Iraqi aircraft bombarded IS hideouts at Balkana area, some 110 km northeast of the provincial capital Baquba, leaving 15 IS militants killed, including local leaders of the group, Lt. Gen. Mezhir al-Azzawi, commander of the security forces responsible for military operations in Diyala, told Xinhua.

Despite repeated military operations in the Diyala province, remnants of IS militants are still hiding in some rugged areas near the border with Iran, and in the sprawling areas extending from the western part of the province to the Himreen mountainous area in north of Baquba, some 65 km northeast of the Iraqi capital Baghdad.

On Dec. 9, 2017, Iraqi Prime Minister Haider al-Abadi officially declared full liberation of Iraq from the IS extremist group.

However, small groups of IS militants have since regrouped in rugged areas, carrying out attacks against security forces and civilians despite the military operations from time to time to hunt them down.