TIKRIT, Iraq, Feb. 8 (Xinhua) -- Six Islamic State (IS) militants were killed Thursday during an operation in a mountainous area in Iraq's central province of Salahudin, a provincial police source said.

A joint force from the police and provincial special forces, known as Rapid Response, backed by Sunni tribal fighters, carried out an operation in the mountain ranges of Himreen and Makhoul in east of the provincial capital Tikrit, Major Salih al-Obeidi told Xinhua.

The operation resulted in the killing of six militants and the destroying of a number of IS hideouts and three of their vehicles along with seizing caches of weapons, ammunition, food and medical supplies, Obeidi said.

The operation came a day after the Iraqi forces launched another major offensive to hunt down terrorist rebel groups of IS, Ansar al-Sunna and the so-called the White Flags, in north and south of the city of Tuz-Khurmato, some 90 km east of Salahudin's capital Tikrit.

The terrorist groups repeatedly carried out attacks against civilians and Iraqi security forces in Tuz-Khurmato and nearby Kirkuk province.

Salahudin's provincial governor, Ahmed al-Jubouri, frequently complained that rebel group has been regrouping in the vast rugged areas in the eastern part of the province that stretch to the neighboring Diyala province and the nearby Himreen mountainous area.

During the past few months, dozens of IS militants fled their former bases in the key cities of the predominately Sunni Arab province of Salahudin, including the provincial capital Tikrit, some 170 km north of Baghdad, after the Iraqi forces cleared these areas during major anti-IS offensives.