The blast occurred at 9:20am (06:00 GMT) in the Shia-dominated area of Binouk, close to a shelter where police were signing-up police recuits. Six of them were injured.
Two soldiers died after three bombs exploded in Sadiyah, 95km north of Baghdad, injuring three others.
Police said one attack caused all five casualties, as a car bomb exploded on an Iraqi base.
A roadside bomb nearby also damaged a police vehicle but the officers inside were not injured.
Immediately afterwards, a suicide bomber attempted to rush the convoy but was deterred by police shooting at him.
After fleeing he blew himself up in a nearby orchard, police said.
An explosion also occurred near a hospital in Sadiyah. Police said there were an unconfirmed number of casualties.