Citing intelligence reports, the source told Xinhua news agency that a commando force carried out the airdrop operation on an IS hideout in the Himreen mountain range, destroying the hideout and killing the four  militants, including a local leader. 

Despite repeated military operations in Diyala, IS remnants are still hiding in some rugged areas near the border with Iran and the vast areas extending from the western part of the province to the Hamreen mountain range in the north of the provincial capital Baquba, about 65 km northeast of Baghdad. 

The security situation in Iraq has been improving since Iraqi security forces fully defeated the IS militants across the country late in 2017. 

However, deadly incidents still occur sporadically in the war-ravaged country as IS remnants have since retreated into urban areas or deserts and rugged areas, waging frequent guerilla attacks against security forces and civilians.