BAGHDAD, Iraq (CNN) -- Dozens of Islamic militants loyal to al Qaeda attacked Shiite Muslim villages north of Baghdad around dawn Sunday, killing more than a dozen people, an Interior Ministry official said.
An Iraqi soldier surveys the damage from a car bomb in Baghdad that left two people dead Sunday.
Iraqi troops and police arrived and chased off the militants, the official said.
Also Sunday, Shiite Police Col. Karim Abdul Hussein was gunned down near his home in Afak, east of the southern provincial capital of Diwaniya.
The assassination comes five weeks after a bombing that killed the province's governor and police chief, along with three bodyguards.
Diyala has been the scene of sometimes-intense fighting between Shiite factions in recent months, and coalition forces have taken on militia fighters in Diwaniya.
Eight more people were killed and 14 were wounded in a gun battle in western Baghdad, and other attacks left at least seven people dead nationwide.
The al Qaeda raids targeted two villages about 25 miles (40 kilometers) north of Baquba. The fundamentalist Sunni fighters, armed with guns and rocket-propelled grenades, struck about 6 a.m. Sunday (10 p.m. Saturday ET).
The Sunni fighters killed 14 people, including three children, wounded 10 others and set 12 houses ablaze, the Interior Ministry official said.
Villagers fought back for about an hour before Iraqi police and army units joined the battle, but there were no casualties reported among the attackers. The jihadists retreated into the countryside with government troops in pursuit after reinforcements arrived, the official said.
In the Baghdad gun battle, which was between security forces and unidentified gunmen, eight people were killed and 14 wounded, most of them civilians, an Interior Ministry official said.
Details were sketchy, but the official said witnesses told police that the security forces involved appeared to be Westerners driving sport utility vehicles, which are usually used by Western companies.
State television network al-Iraqiya reported that a Western security company was involved in the shootout, but it did not identify the firm.
In a statement carried on the network, Prime Minister Nuri al-Maliki said his government would punish those responsible and bar the company involved from working in Iraq.
An estimated 25,000-plus employees of private security firms are working in Iraq, guarding diplomats, reconstruction workers and government officials. As many as 200 are believed to have been killed on the job, according to U.S. congressional reports.
The clash occurred near Nisoor square, in western Baghdad.
In addition, one person was killed and seven wounded in a car bomb in the Mansour district, also on Baghdad's west side, the official said. And in eastern Baghdad, a mortar round killed one person and wounded three others when it landed near Shaab stadium Sunday morning.
In northern Iraq, five people died and 22 were wounded when a suicide bomber detonated his explosives vest in a popular restaurant in Tuz Khurmatu, a mainly Turkmen town about 106 miles (170 kilometers) north of Baghdad, a Kirkuk police official told CNN.
Suspect nabbed in sheik slaying
Coalition forces arrested a suspected al Qaeda in Iraq insurgent they say is linked to last week's assassination of a Sunni sheik who had been helping U.S. forces battle the terrorist organization in Anbar province, the U.S. military said Sunday.
Fallah Khalifa Hiyas Fayyas al-Jumayli, also known as Abu Khamis, was captured Saturday during a raid on three buildings west of Balad, the military said.
"When the buildings were secure, one of the residents positively identified al-Jumayli," the military said, adding that three additional suspects also were detained.
Al-Jumayli has been linked to plots to kill Anbar's key tribal leaders who are "committed to driving al Qaeda in Iraq out," the military said.
Abdul Sattar Abu Reesha, the 39-year-old head of the Anbar Salvation Council, was killed Thursday when a roadside bomb detonated near his home in Ramadi, Iraqi officials said. At least two of Reesha's bodyguards also died in the blast, officials said.
The Anbar Salvation Council -- also known as Anbar Awakening -- is a coalition of tribes working with the U.S. military to counter al Qaeda influence in the Sunni-dominated province. Watch how U.S. forces are tracking and attacking insurgents from the sky »
Al Qaeda in Iraq claimed responsibility for the sheik's assassination in a message posted on an Islamist Web site.
"Your brothers in the security ministry of the Islamic State of Iraq have assassinated the imam of the infidels and of the apostasy, Abdul Sattar Abu Reesha, one of the dogs carrying Bush's flag," the statement says.
CNN could not confirm the authenticity of the statement. Islamic State of Iraq is an umbrella group for several terrorist organizations, including al Qaeda in Iraq.
Anbar Awakening, an outfit funded and supported by al-Maliki, was formed last year. Al-Maliki blamed al Qaeda in Iraq for Reesha's killing.
Sadrist bloc leaves Shiite alliance
The political bloc led by radical Shiite cleric Muqtada al-Sadr withdrew from the United Iraqi Alliance, the Shiite bloc that leads the Iraqi government, a spokesman for al-Sadr said.
Parties within the alliance are "working for their own interests" by pursuing government posts instead of the people's agenda, said spokesman Salah al-Obeidi.
The decision was announced Saturday evening in Najaf after members of the Sadrist bloc met with members of the Fadhila party, which withdrew from the UIA in March.
Al-Sadr's group will now begin forming political alliances with groups that share its goals, al-Obeidi said.
The UIA initially was made up of four Shiite factions -- the Sadr group, the Supreme Islamic Council of Iraq, the Dawa Party and the Fadhila Party -- and held 130 seats in the 275-member parliament.
That number dropped to 115 when the Fadhila Party left. The Sadr bloc has 30 seats in parliament, which were not affected by the withdrawal.
In April, al-Sadr ordered six Cabinet ministers from his bloc to leave the government after al-Maliki rejected a timetable for the withdrawal of U.S.-led troops.
Al-Sadr's movement controls the ministries of Health, Agriculture, Province Affairs, Transportation, Tourism and Civil Society Organizations. E-mail to a friend
CNN's Mohammed Tawfeeq and Jomana Karadsheh contributed to this report.