The U.N. mission said Thursday that the attacks occurred on Tuesday and Wednesday in eastern Mosul, where Iraqi troops are battling Islamic State militants. It says up to 40 other people were wounded in the attacks.
The U.N. did not identify the aid workers or provide their nationalities.
On Wednesday, Human Rights Watch said Islamic State fighters are deliberately targeting civilians in areas they have lost to government forces. Iraq launched a major offensive in October to retake Mosul, the country’s second largest city.