The attacks came during a ceremony marking National Police Day, the anniversary of the formation of Iraq's national police force. Police Sergeant Abd al-Hadi Hasan suggested that many of those killed were police officers.
An Internet website claims that the Al-Qaeda in Iraq group headed by Abu Mus'ab al-Zarqawi was responsible for the attacks. The authenticity of that claim could not be immediately verified.
Also today, gunmen in Kirkuk assassinated an investigative judge.
In separate attacks in Baghdad, gunmen killed a member of Iraq's de-Ba'athification commission, an Iraqi intelligence officer, and a doctor.
U.S. military officials have confirmed that eight U.S. soldiers and four U.S. civilians were killed late on 7 January when an Army helicopter crashed in Iraq.