The Iraqi ministry of health says more than 1,500 people were killed in attacks in Baghdad last month.
Sectarian and insurgent killings in Baghdad are undiminished
The figure is far higher than previously thought, and only slightly lower than July's figure.
US military and Iraqi officials had previously said a major new security operation in Baghdad had dramatically reduced the number of killings.
In the latest violence, three people were killed by a bomb in the Karrada district on Friday.
The bomb apparently targeted a local police commander, who survived the attack.
And in a separate development, at least five Iraqi border guards were seized on the border with Iran, and are being held in Iranian custody.
The guards were detained during an incident on Thursday, details of which are not clear.
One report says there was an exchange of fire before the Iraqis were taken prisoner.
American forces, who were patrolling the border with the Iraqis, withdrew from the area with no injuries.
BBC Baghdad correspondent David Loyn says mistakes are easy to make along this section of the border, with different maps showing the border in different places.
The Iraqi health ministry says its final count for violent deaths in Baghdad in August is 1,536.
That is nearly three times the same ministry's estimate issued last week.
Correspondents say this indicates a nearly undiminished level of sectarian and insurgent killings.
Last month the US military spokesman in Iraq, Maj Gen William Caldwell, said the rate of violent deaths in Baghdad had fallen significantly from July to August.
US officials had suggested that the murder rate in Baghdad had dropped 52% in August compared to the daily rate for July.
The health ministry's figures are complied from reports by hospitals and mortuaries in Baghdad area.