BAGHDAD, June 30 (Xinhua) -- A soldier was killed and three wounded Saturday in an attack by Islamic State (IS) militants at a rural area in the northwestern part of Iraq's eastern province of Diyala, a provincial official said.

The extremist militants attacked in the early morning an outpost in the village of Albu Sliebi near the provincial border with Salahudin province, Udai al-Khadran, mayor of the town of Khalis, some 70 km northeast of Baghdad, told Xinhua.

The two sides sparked heavy clashes, leaving a soldier killed and three others wounded.

Iraqi reinforcement troops dispatched to the scene and retook control of the area, conducting a search operations looking for the attackers, Khadran said without giving further details.

The extremist militants also carried out an attack on Friday on a village in the rugged area in northwestern Diyala province, but were repelled by the security forces and villagers, leaving five villagers wounded, according to a provincial security source.

Recently, IS militants repeatedly carried out attacks on security forces and civilians, abducting dozens of people at fake checkpoints on a main road between Baghdad and Kirkuk, which passes through the northwestern part of Diyala and the eastern part of neighboring Salahudin province.

During the past months, hundreds of IS militants fled their former urban strongholds in Mosul, Salahudin Province and Hawija area in the west of Kirkuk, after Iraqi forces took over these regions in major offensives.

On Dec. 9, 2017, Abadi officially declared full liberation of Iraq from 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.