At least 16 soldiers and government-backed militiamen were killed in clashes with Islamic State (IS) militants in Iraq's northern central province of Salahudin, a provincial security source said on Thursday.

The IS militants launched an attack late Wednesday on a military base outside the town of Dijla, also known as Mkeshifah, some 40 km south of the provincial capital of Tikrit, and seized it, the source told Xinhua on condition of anonymity.

The attack started when they pushed a suicide bomber, who drove a booby-trapped armored vehicle at the entrance of the base and blew it up before dozens of IS militants followed inside the base, the source said.

The battle continued until early Thursday morning when reinforcement troops, backed by allied Sunni and Shiite militias, launched a counterattack and drove out the extremist militants, the source added.

Eleven soldiers and government-allied militiamen were also wounded in the fighting.

Dozens of IS militants were killed or wounded, the source said without giving further details.

The troops also found two booby-trapped armored vehicles near the battlefield, which were defused later by explosive experts, the source said.

Salahudin, a predominantly Sunni province with its capital of Tikrit, some 170 km north of Baghdad, is the hometown of former President Saddam Hussein.

Security has deteriorated drastically since June 10, when bloody clashes broke out between Iraqi security forces and Sunni militants, who seized the northern city of Mosul and later swathes of territories in Nineveh and other predominantly Sunni provinces.