BAGHDAD, April 7 (Xinhua) -- Iraqi forces on Sunday dismantled three Islamic State (IS) sleeper cells and arrested a number of IS militants, including a prominent group leader, in Iraq's eastern province of Diyala, a provincial security source said.

Diyala's intelligence service, backed by the Iraqi army and police, conducted operations to hunt down IS militants in separate areas of the province, Sadiq al-Husseini, head of the security committee of the provincial council, told Xinhua.

The troops arrested a number of the extremist militants, including a prominent group leader said to be "the head of the snake" in the province, al-Husseini said.

The security forces believe that the prominent leader is a close aide to IS top leader Abu Bakr al-Baghdadi, according to al-Husseini, who refused to give further details for security reasons.

Also in the province, a force from the intelligence service ambushed and arrested three IS leaders at a rural area near the village of Mkheisa in northeast of the provincial capital Baquba, some 65 km northeast of Baghdad, al-Husseini said.

The three leaders are "very dangerous and very important for the structure of the terrorist organization of the province," he said without disclosing their names or nationalities.

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

On Dec. 9, 2017, Iraqi Prime Minister Haider al-Abadi officially declared full liberation of Iraq from the IS. However, small groups of IS militants have since regrouped in rugged areas, carrying out attacks against security forces and civilians from time to time.