One of the attacks occurred after midnight when ISIL 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 ISIL 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 ISIL 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 ISIL 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-ISIL international coalition carried out a major offensive to drive out ISIL militants from its last major stronghold in Mosul.
Many blame the current instability, violence, and emerging extremist groups - such as the ISIL - on the US, following its invasion of Iraq in March 2003 and subsequent occupation.
XINHUA/MNA