Five died in a car bomb attack in the town of Tal Afar, west of Mosul, on Tuesday. The blast also wounded eight people, including seven children.
Hospital and police sources said earlier the bombs targeted US and Iraqi troops.
"The suicide bomber detonated prematurely after soldiers at the checkpoint opened fire at him as he approached them," said witness Muhammad Rida Jasim.
Doctor Muhammad Khalil at Tal Afar's hospital said it received four dead and 12 wounded from the attack and that edgy Iraqi soldiers had beaten an ambulance driver who arrived at the scene shortly after the attack.
The blast left a hole in the road
In another attack on Tuesday, five Iraqis were killed and 12 wounded when a car bomber blew up in the central Al-Muthana neighbourhood near a US military convoy, witnesses said.
"The driver entered through an opening in the road and made a sharp U-turn and blew himself up in between three armoured vehicles," said shopkeeper Ayman Muhammad, 41.
"It was a massive blast; the whole ground shook underneath."
An AFP correspondent said he saw a hole in the road left by the blast with remains of the vehicle and the bomber's remains strewn nearby. Two other vehicles were reduced to twisted metal and several nearby buildings were badly damaged.
Hospital Doctor Ahmad Abd Allah Rajab said his facility received five bodies, two of them completely charred and blackened, and three wounded, including a woman.
"The driver entered through an opening in the road and made a sharp U-turn and blew himself up in between three armoured vehicles"
The US military confirmed both attacks in the city without saying its soldiers were the targets.
Earlier, four people were wounded when a car bomber blew himself up near a US military patrol at about 4pm (1200 GMT) in the old al-Sinai neighbourhood on the western side of the city, an Iraqi policeman said.
Since November, Mosul has become a new front for the anti-US campaign, with nearly daily assassinations of Iraqi officials and security force members, and car bombings against US and Iraqi forces.
A US official said on Monday there was an alarming escalation in car bombings against US convoys in Mosul over the past few weeks.