World Bulletin / News Desk
The device exploded as a police patrol was passing north-east of Baquba city in Diyala province, Captain Habib al-Shammari said.
No group has claimed responsibility for the attack.
Al-Shammari said an investigation has been launched into the attack.
Attacks against security forces and civilians have been on the rise in Diyala province in eastern Iraq in recent weeks.
Last December, officials in Baghdad declared that the ISIL terrorist group's military presence in Iraq had been all but dismantled after a three-year war.
However, from time to time, Iraqi officials announce operations against ISIL-affiliated "sleeper cells" in certain parts of the country.