The killings at the military barracks in the village of Ayn al-Jahish outside of Mosul mirrored two previous assaults earlier this year in the area targeting security forces. It also represents the latest blow to the government's efforts to achieve stability in restive Sunni-dominated areas.
Gunmen staged the assault late Saturday night, two police officers said, shooting some at short range while others died fighting the insurgents when they stormed the barracks. A medical official, who confirmed the causality number, said 11 troops had their hands tied behind their backs and suffered close-range gunshots to the head.
The slain troops are in charge of protecting an oil pipeline that sends Iraqi crude oil to international markets and guarding a nearby highway. Attacks on the pipeline are common in that area near Mosul, located about 360 kilometers (225 miles) northwest of Baghdad.
No group immediately claimed responsibility for the barracks attack. However, it mirrored a February attack in the area claimed by the al-Qaida-breakaway group Islamic State in Iraq and the Levant. In that one, fighters from the group killed 15 soldiers at the barracks, beheading some of them. In April, militants killed at least 10 soldiers at a base outside of Mosul.
Mosul, Iraq's second-largest city is a former insurgent stronghold. It was al-Qaida's last major urban stronghold in the country before U.S. troops wrested back in 2008. However, Sunni insurgent groups remain strong in the region long after the U.S. withdrawal from the country, challenging Iraq's Shiite-led government.
Recent attacks come amid a surge in violence to levels unseen in Iraq since 2008. Last year, Iraq saw its highest annual death toll since 2007 with 8,868 people killed, according to United Nations figures.
The insurgents also have been emboldened by the civil war in Syria, where rebels are fighting to oust the regime of President Bashar Assad, a follower of a Shiite offshoot sect. The rebels are dominated by Islamists and members of al-Qaida-linked or inspired groups, including the Islamic State of Iraq and the Levant. Shiite militiamen from Iraq fight on the side of Assad's forces.
It's been the most serious challenge to the government's efforts to achieve stability in Iraq, which just had its first parliamentary election since the U.S. withdrawal. Confrontations over Sunni protests in December saw security forces withdraw from areas in Anbar province, allowing militants to take over the city of Fallujah and parts of the provincial capital of Ramadi.
Other attacks continued Sunday.
In the town of Adeim, about 100 kilometers (60 miles) north of Baghdad, gunmen in speeding car opened fire on members of the Sahwa militia, which joined forces with U.S. troops at the height of the Iraq war to fight al-Qaida, killing seven, a police and an military officers said.
Outside of Mosul, gunmen attacked a joint checkpoint for Iraqi police and the Sahwa, killing three police officers and one Sunni militiaman, another police official said. Another Sahwa member was killed along with his brother and son when gunmen stormed his house in the town of Youssifiyah, 20 kilometers (12 miles) south of Baghdad.
Medical officials confirmed the casualty figures. All officials spoke on condition of anonymity as they were not authorized to release the information to journalists.
Follow Sinan Salaheddin on Twitter at www.twitter.com/sinansm.
Associated Press writer Sameer N. Yacoub contributed to this report.