Three Iraqi soldiers were killed and one was wounded in an attack on a checkpoint in Balad, north of Baghdad, on Saturday.
In Tikrit, also north of Baghdad, five Iraqi soldiers were killed and seven were wounded when a bomber blew his car up at the entrance of a military base.
And in Falluja, west of Baghdad, an Iraqi soldier was killed and two were wounded in another attack.
In another development on Saturday, US-led and Iraqi forces arrested one of the leaders of the Kurdish group Jaish Ansar al-Sunna, in the northern city of Mosul.
Mulla Mahdi was detained along with his brother and three non-Iraqi Arabs on Saturday.
Guard unit disbanded
Meanwhile, an Iraqi national guard unit has been disbanded after it refused to attend a military training academy overseen by US advisers, former members of the unit said on Saturday.
The soldiers, part of a 90-strong force that calls itself the Defence Force of Rutba, said they feared reprisals from locals if they were seen to be cooperating with the Americans.
"We refused to go because we were afraid that when we came back to Rutba we would be killed," Taha Allawi, a former member of the unit, said. Rutba is in the far west of Iraq, close to the border with Jordan.
"We refused to go because we were afraid that when we came back to Rutba we would be killed"
Former Iraqi soldier
A US military official who oversees training said Iraqis who refused to attend courses could be dismissed, but said the decision rested with Iraq's Ministry of Defence.
He said the unit in question was believed to be a former Iraqi National Guard unit that was due to be integrated into the Iraqi army.
Its members had refused to attend the Kirkush camp where Iraqi officers run courses overseen by US advisers.
Iraq's Defence Ministry had no immediate comment.
Another former soldier in the force, Ahmed Dhahi, said the disagreement began two months ago when he said the US military first raised the idea of them attending a training course.
US-trained Iraqi soldiers are
routinely targeted by fighters
"They told us we had no right to refuse, they said the duty of soldiers was to obey orders, but we said: 'We are Iraqis, not Americans, we don't follow orders from Americans'," he said.
"We did not want the locals to think that we were working with the Americans and then threaten us."
Dhahi said that once it became clear that the unit would not attend, the US military took away their weapons, uniforms and identification tags and dismissed the force.
Iraqi units have fled the frontline when ordered to fight anti-US fighters before, but this is believed to be the first case of soldiers refusing to attend training for fear of reprisals.
Sunni Arab town
Rutba, on the main highway heading to Jordan, is a predominantly Sunni Arab town with strong tribal allegiances.
It has been the scene of occasional violence over the past two years, including attacks on military convoys.
A member of Rutba's local council said the soldiers, who had been receiving a salary of about $300 a month, were right to refuse to attend the course.
"The soldiers have all the right if they refuse to go because we understand the reason why they have taken this position," said Hamid Saleh al-Kubaisi.
"We have tried many times over the past two months to get the Americans to change their order, but they have insisted that they must go. The council has no effect on anything because the Americans don't listen."