At least 15 security members were killed and five others were abducted during overnight attacks by extremist Islamic State (IS) group militants against military bases in Iraq's Salahudin province, said a provincial security source on Wednesday.

One of the attacks occurred after midnight when IS militants assaulted a police commandos outpost in a rugged area by the provincial border between Salahudin and Iraq's eastern province of Diyala, killing at least 11 police commandos and wounding eight others, the source told Xinhua on condition of anonymity.

The attackers kidnapped five police commandos before they fled the scene, the source said.

Meanwhile, fierce clashes took place when dozens of IS militants with heavy machine guns, mortar and rockets blasts advanced toward the paramilitary Sunni tribal fighters posts in the area of Jillam al-Dour in Tikrit, 170 km north of Baghdad, the source said.

The fighters, part of the government-backed Hashd Shaabi units, repelled the attack, killing three IS militants and destroying one of their vehicles, while four paramilitary fighters were killed with nine others wounded, the source added.

A third onslaught occurred when IS militants attacked the Ajil oil field, 30 km east of Tikrit.

However, security forces backed by the army's helicopter squad repelled the attack, killing three militants and destroying one of their vehicles which was carrying a heavy machine gun.

Three police force members tasked with protecting the oil field were wounded during the clashes, he said.

Salahudin's vast rugged open land has witnessed major offensives in order to drive out extremist militants and prevent them from using the province in their attacks against civilian and military targets, in the provinces of Diyala and Salahudin.

The attacks came as Iraqi security forces backed by the anti-IS international coalition carried out a major offensive to drive out IS militants from its last major stronghold in Mosul.

Many blame the current instability, violence, and emerging extremist groups - such as the IS - on the U.S., following its invasion of Iraq in March 2003 and subsequent occupation.

source: Xinhua