BAGHDAD, Iraq (CNN) -- U.S. forces killed at least six Iraqi security troops after Iraqi personnel mistakenly fired on an American patrol boat north of Baghdad on Wednesday, an Iraqi Interior Ministry official said.
Ten people were also wounded in the firefight, which occurred at an Iraqi checkpoint along the Tigris River north of the Sunni Arab town of Tarmiya. The checkpoint was manned by Iraqi security forces and Awakening Council members.
The Interior Ministry official said the forces mistakenly opened fire on a U.S. military patrol boat. A U.S. chopper returned fire, causing the casualties, the official said.
Another Interior Ministry official said that the incident took place early Wednesday and that the security personnel didn't realize they were firing on U.S. troops.
This official said that among the six who were killed, three were police, two were soldiers and one was an Awakening Council member.
The U.S. military didn't elaborate on the sequence of events but confirmed coalition forces had been conducting operations against al Qaeda in Iraq militants when there was "weapons fire between coalition and Iraqi security forces."
"It is always regrettable when incidents of mistaken fire occur on the battlefield. A review of the circumstances is under way," a military official said.
The deadly incident comes two days after a teenage suicide bomber launched an attack in Tarmiya that badly wounded Imad al-Mashhadani, the head of the town's Awakening Council.
Awakening Councils are predominantly Sunni fighters supported by the United States who have turned against al Qaeda in Iraq.
Separately, coalition troops in northern Iraq on Wednesday killed a suspected al Qaeda in Iraq operative believed to be moving rockets and bomb parts for a cell in Tikrit, the U.S. military said.
The operation -- which took place in Tikrit -- targeted an al Qaeda bombing network, which included the "weapons facilitator."
When troops arrived at a building, they told people inside to surrender. While several people emerged, one man remained inside.
"During a security sweep of the building, coalition forces found the terrorist, dressed in women's clothing and hiding under a bed with a rifle and military-style assault vest," the military said.
"Perceiving hostile intent, coalition forces engaged and killed the armed terrorist, who was later determined to be the weapons facilitator."
Five other people were arrested, and arms were seized.
In another raid in Tikrit, another member of the cell was detained and a weapons cache was found outside his house. Farther south of Tikrit near Tarmiya, two people were seized in a raid targeting "liaisons" between senior al Qaeda in Iraq leaders," the military said.
CNN's Jomana Karadsheh and Mohammed Jamjoom contributed to this report.