Three persons, including a senior officer, were killed on Wednesday when unidentified armed men attacked his convoy in a residential neighborhood northeast of Baquba, Al Sumaria news channel reported, quoted a security source as saying.
A civilian was injured in the attack, the source added.
Security forces cordoned off the area.
An investigation has been launched into the incident.
Iraq has been in turmoil since the ouster of Saddam Hussein during the US invasion of the country nearly 13 years ago.