BAQUBA, Iraq, Jan. 25 (Xinhua) -- Four Islamic State (IS) militants were killed Thursday in an airstrike and a bomb explosion in Iraq's eastern province of Diyala, a provincial police source said.

In one incident, a helicopter gunship pounded an IS hideout in Wadi-Thlab, some 90 km northeast of the provincial capital Baquba, destroying the hideout and killing the three militants inside, Major Ali al-Timimi told Xinhua.

Separately, another IS militant was killed while trying to plant a roadside bomb at a main road in al-Zour area, some 50 km northeast of Baquba, Timimi said, adding that the killed militant is wanted for involvement in previous bomb attacks.

Despite repeated military operations in Diyala province, remnants of IS militants were still hiding in rugged areas near the border with Iran in eastern Diyala, as well as the sprawling areas extending from western part of the province to Himreen mountainous area.

The militants are still capable of carrying out attacks against civilians and the security forces despite operations from time to time to hunt them down.

Meanwhile, Ali al-Dayni head of Diyala's provincial council, told Xinhua that militiamen distributed leaflets threatening the residents to leave their houses in Bablan al-Bazani village in east of the town of Maqdadiyah, some 40 km northeast of Baquba, otherwise the militiamen will attack them.

"What is going on in the village entails dispatching security forces to arrest anyone trying to bring back the sectarian violence to the province of Diyala," Dayni said, without giving details about the identity of the militiamen who are threatening the Sunni Arab villagers.

Like most of the Iraqi provinces, Diyala has been suffering from sectarian tension and reprisal killings between Sunni and Shiite communities, particularly in the years after the U.S.-led invasion in 2003 that killed and wounded dozens of thousands of Iraqis.