The attack occurred shortly after 2 am (2300 GMT) in the town of Khan Bani Saad, about 30 km (20 miles) northeast of Baghdad, the head of the local security committee and police said.
“An attack of this size, in which the five killed makes up the total (number of) staff at the checkpoint, indicates that al-Qaeda sleeper cell groups are now re-activating their movements,” said Saad Abdullah, head of the security committee in Khan Bani Saad.
“The government should move quickly to crack down on these al-Qaeda cells.”
Al-Qaeda affiliated groups might strengthen again after the departure of US troops on December 18, according to local agencies. US led forces invaded Iraq nearly nine years ago and toppled Saddam Hussain.
Al-Qaeda’s affiliate in Iraq, the Islamic State of Iraq, has been involved in various bloody attacks. It has claimed responsibility for multiple bombings around Baghdad that killed at least 72 people on December 22.
Members of the Sahwa, a Sunni militia that voiced and took up arms against al-Qaeda and helped stop Iraq’s sectarian strife becoming a full-scale civil war, are the prime targets of al-Qaeda’s aggression.