The attack occurred shortly after 2 a.m. (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 reactivating 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-linked insurgents are still capable of carrying out lethal attacks and there are worries they may may try to regroup following the withdrawal of US troops on Dec. 18, nearly nine years after the invasion that toppled Saddam Hussein.

Al-Qaeda’s affiliate in Iraq, the Islamic State of Iraq, claimed responsibility for multiple bombings around Baghdad that killed at least 72 people on Dec. 22.

Members of the Sahwa, a militia that took up arms against Al-Qaeda and helped stop Iraq’s sectarian strife from becoming a full-scale civil war, are frequent targets of the insurgency.

On Friday, a Sahwa militia member and three of his bodyguards were killed when a sticky bomb attached to their car exploded in Taji, 20 km (12 miles) north of Baghdad, police said.