Two other members of the Awakening Council in Tarmiyah were reported missing after the blast.
Lieutenant Ahmed Abdullah, the police spokesman, told AFP news agency that he believed that their bodies might have been ripped apart in the explosion.
“The suicide bomber, driving a truck, went into the checkpoint and exploded the vehicle,” he said.
Abdullah said that the five children killed, aged about 15, were crossing the road to school when they were hit by the explosion.
Al-Qaeda previously held a strong position in Tarmiyah but its fighters have been pushed back by members of the Awakening Councils.
Also on Monday, suspected al-Qaeda fighters attacked Dalli Abbas village near the Diyala provincial capital of Baquba, killing three people and wounding 10, police said.
Another three people were killed in a similar attack in a village near the city of Samarra.
“Clashes erupted between residents and al-Qaeda operatives who attacked Tal al-Thahab village. Three villagers and two of the attackers were killed,” the official said.
In a message posted on the internet on Saturday, bin Laden said the Awakening Councils had “betrayed the nation and brought shame and scandal that will be followed by damnation forever unless they repent”.
Bin Laden ‘weak’
The Awakening Councils hit back on Monday, accusing the al-Qaeda leader of being un-Islamic and calling him weak.
“Bin Laden’s statement doesn’t affect us – he is making these threats from a position of weakness,” Sheikh Khalid Shahudh, a senior member of the Awakening Council in western Anbar province, said.
“Al-Qaeda has no more power in Anbar province,” Shahudh told AFP.
“The Awakening is now operating all across Iraq and involving all sects. We will continue chasing al-Qaeda. We have no enemies except al-Qaeda. The Americans are not our enemy anymore.”
The council in central Salaheddin province, in a statement, accused bin Laden and his followers of being un-Islamic.
“What the loyalists of bin Laden do contradicts Islamic principles and its moral standards,” it said.
“Bin Laden should order his followers to stop targeting Iraqis… he must apologise to Iraqis that have been harmed by al-Qaeda’s heinous crimes.”