BAGHDAD: Gunmen carrying silenced weapons attacked a checkpoint manned by government-backed Sunni militiamen and killed all five of them in the restive Iraqi province of Diyala, security officials said on Saturday.

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 linked insurgents are still capable of carrying out lethal attacks and there are worries they may try to regroup following the withdrawal of US troops on December 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 December 22.

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