BAGHDAD, Aug. 25 (Xinhua) -- A leader of Islamic State (IS) militants was killed in a fire between two IS groups in Iraq's eastern province of Diyala.

Separately, two of the extremist militants were killed in clash with the security forces in the province, provincial security sources said on Saturday.

Intelligence reports confirmed that Abu Ahmed, a local IS leader was killed in a clash between two IS groups at the orchards of Mkheisa area in northeast of the provincial capital Baquba, some 65 km northeast of Baghdad, Ahmed al-Shimary, from Diyala Operations Command, told Xinhua without saying when the incident took place.

Ahmed was one of the aides of the former al-Qaida top leader Abu Musab al-Zarqawi, who was killed in a U.S. airstrike in 2006, Shimary said.

Ahmed, who is an Iraqi national, joined IS extremist militant group in 2014 and became one of the main group's leaders in Diyala province.

Separately, a joint Iraqi army and police force killed on Saturday two IS militants and destroyed their vehicle while they were trying to transfer fuel to the extremist militants in Himreen mountainous area in north of Diyala province, Sadiq al-Husseiny, head of the provincial security committee, told Xinhua.

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.