There was no immediate claim of responsibility for the attack in which an improvised explosive device was used in a remote area between the cities of Kirkuk and Arbil, the capital of the autonomous Kurdistan region.
"Two officers, including a colonel, were killed and four soldiers were wounded" when their vehicle drove over the IED, an Iraqi military source said on condition of anonymity.
A medical official gave the same toll.
Islamic State group fighters still carry out sporadic attacks in Kirkuk province, even after the jihadists were defeated in Iraq in 2017 and two years later in Syria.
IS had swept over the neighboring countries in 2014 and set up a "caliphate" in which they brutally imposed their extreme interpretation of Islamic law.
Since losing its last redoubts in Iraq and Syria, the group has been reduced to small bands of guerillas operating in remote areas but no longer controlling any territory.
Iraqi security forces insist they are now capable of tackling IS remnants unassisted, as the group poses no significant threat.
At the end of August, a joint operation by US and Iraqi forces killed 15 IS group fighters in Iraq's western desert, with seven US troops wounded in the operation, US Central Command said at the time.
A UN report released in July found the group's combined strength in Iraq and Syria had fallen to between 1,500 and 3,000 fighters as a result of "battlefield losses, desertions, and recruitment challenges".
In Iraq, its "activities remain largely contained but the group remains capable of sporadic, impactful attacks," the UN report found.