The spokesman for the Salahuddin province police force, Col Mohammed al-Jabouri, said three militants rammed their explosives-laden vehicles early this morning into the main check point at the province's northern entrance. Al-Jabouri added that 34 other security officers were wounded.
He said the attack occurred as the local police chief and head of the provincial security committee were visiting the site. Both escaped unharmed.
No group has claimed responsibility for the attack, but IS militants have claimed multiple similar attacks. The Sunni extremists frequently launch attacks targeting Iraq's security forces and civilians in public areas.
In April 2015, Iraqi security forces drove out Islamic State militants from the Salahuddin provincial capital, Tikrit, about 130 kilometers north of Baghdad. The attack came days after government forces recaptured the town of Shirqat, north of Tikrit, from IS militants.
Backed by the US-led international coalition and paramilitary forces, the Iraqi government is gearing up for a major military operation to dislodge the militants from the city of Mosul.
The city, about 360 kilometers northwest of Baghdad, is the last major IS urban stronghold in Iraq. US officials have said for some time that they expect the Mosul operation to begin in October.