At least 1,370 people were wounded during the same period, the UN Iraq mission said in a statement.
It said the figures did not include Anbar province, west of Baghdad, and that there were difficulties in verifying incidents in areas where there was fighting or which were outside government control.
Militants led by the Islamic State (IS) jihadist group overran chunks of five provinces in June, sweeping security forces aside.
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After a period of largely static battle lines, the militants launched a renewed offensive in the north in early August, driving Kurdish forces back towards their regional capital, displacing hundreds of thousands of people and prompting Washington to launch air strikes.
Kurdish fighters with US air support have managed to claw back some of the lost ground in the north, and there has also been heavy fighting northeast of Baghdad.
Militants have also carried out a spate of bombings that have caused heavy casualties.