Five other soldiers were wounded when the bombs exploded simultaneously at about 2 a.m. as the patrol was responding to a call for aid at a police station near the village of Jalula, said a security official at the provincial security headquarters in Diyala province.
The apparent coordinated attack is the latest effort by insurgents who have targeted Iraqi security forces in their bid to disrupt recent security gains that have led to a sharp decline in violence in Iraq.
A third roadside bomb exploded in the same area minutes after the double blast, but caused no damage, said the security official, who spoke on condition of anonymity because he was not authorized to release information to the media.
The U.S. military said initial reports showed six Iraqi soldiers were killed and three were wounded during the attack. The Iraqi police initially reported five killed and eight wounded, but later revised its numbers.
Conflicting reports on the number of dead and wounded are common in Iraq in the chaotic aftermath of attacks.
The security official said the Iraqi army patrol was responding to the location where the mortars were believed to have been fired at the police station, when the explosions occurred.
In a separate attack, two Iraqi soldiers were killed and two were wounded when a roadside bomb targeting a patrol exploded Thursday morning near the village of al-Rashad, southwest of Kirkuk, said police Brigadier Sarhat Qadir.