Iraqi officials say coordinated suicide attacks kill 10 troops and militiamen north of Baghdad

In this Friday, June 12, 2015 photo, fighters from the Shiite Badr Brigades militia patrol at the front line, in Kessarrat, (70 kilometers) northwest of Baghdad, Iraq. Despite concerns over heightened sectarian strife, Shiite militiamen continue to pour into Iraq’s Anbar province with the hope of recapturing the city of Fallujah from the Islamic State group. As the U.S. prepares to send an additional 450 trainers to Iraq, the Iranian-backed militias say that coalition assistance only hurts their efforts, contradicting statements by the Iraqi government that more international support is needed. (AP Photo/Hadi Mizban) (The Associated Press)

In this Friday, June 12, 2015 photo, fighters from the Shiite Badr Brigades militia patrol at the front line, in Kessarrat, (70 kilometers) northwest of Baghdad, Iraq. Despite concerns over heightened sectarian strife, Shiite militiamen continue to pour into Iraq’s Anbar province with the hope of recapturing the city of Fallujah from the Islamic State group. As the U.S. prepares to send an additional 450 trainers to Iraq, the Iranian-backed militias say that coalition assistance only hurts their efforts, contradicting statements by the Iraqi government that more international support is needed. (AP Photo/Hadi Mizban) (The Associated Press)

In this Friday, June 12, 2015 photo, an Iraqi army armored vehicle with a poster of Iranian Shiite spiritual leader Grand Ayatollah Ali al-Sistani patrol at the front line, in Kessarrat, (70 kilometers) northwest of Baghdad, Iraq. Despite concerns over heightened sectarian strife, Shiite militiamen continue to pour into Iraq’s Anbar province with the hope of recapturing the city of Fallujah from the Islamic State group. As the U.S. prepares to send an additional 450 trainers to Iraq, the Iranian-backed militias say that coalition assistance only hurts their efforts, contradicting statements by the Iraqi government that more international support is needed. (AP Photo/Hadi Mizban) (The Associated Press)

Authorities in Iraq say coordinated suicide attacks targeting security posts have killed 10 people north of Baghdad.

Police officials say four suicide bombers driving explosive-laden cars rammed into two security checkpoints and a military headquarters in the al-Hajaj area on Saturday, killing 10 Shiite militiamen and troops. They say at least 20 people were wounded.

Al-Hajaj lies on the road between Beiji and Tikrit in Salahuddin province.

Police said the four suicide attacks took place within a 15-minute period.

Hospital officials confirmed the casualty figures. All officials spoke on condition of anonymity as they weren't authorized to speak to journalists.

Iraqi forces, backed by Shiite militias, have been struggling to regain control of vast areas lost to the Islamic State group during its stunning blitz last year.