ISIS car bombs have killed 23 people in a district of Mosul recently liberated from the extremist jihadi group.
Eight of the dead were policemen and 15 were civilians, according to the Iraqi Defence Ministry.
Iraqi troops entered Gogjali, in the east of Mosul, in early November.
Three suicide bombers were behind the attack in the district, ISIS said when it claimed responsibility.
Also on Thursday, four Iraqi aid workers and at least seven civilians were killed when a mortar attack hit a distribution of aid in the city.
It was the second attack on aid workers and civilians in less than a week.
Three vehicle-borne improvised explosive devices went off in Kokjali, an eastern suburb that the authorities said they had retaken from the jihadis almost two months ago.
At least two civilians were killed and 20 others wounded, including soldiers, according to local police, a health official and a witness. The death toll was expected to rise.
A UN statement on the two separate mortar attacks this week that killed aid workers and wounded about 40 people said indiscriminate shelling violated international law.