BAGHDAD, Iraq (CNN) -- Coalition forces killed nine Iraqi civilians, including a child and two women, and wounded three others near Iskandariya, Iraq, over the weekend, police and a U.S. military spokeswoman said Monday.
Officials are taking a closer look at security in Mosul after a suicide attack last month killed a police official.
Two children were among the wounded in the Saturday incident. The injured were treated at U.S. military hospitals.
Two women were among the bodies taken to Iskandariya's main hospital, a Babil police official said. The dead appeared to be from two Sunni tribal families, the official said.
The official added that a U.S. airstrike in Tal al-Samar, Iraq, caused the casualties. Tal al-Samar is just outside Iskandariya.
The U.S. military provided few details, but Lt. Col. Maura Gillen, an Army spokeswoman, said forces were pursuing suspected al Qaeda in Iraq militants south of Baghdad when the incident occurred.
The military is conducting an investigation, and leaders of the coalition force met with a sheik representing local citizens, she said.
"We offer our condolences to the families of those who were killed in this incident, and we mourn the loss of innocent civilian life," Gillen said.
News of the incident came as a U.S. military commander said that an increase in troops had transformed an insurgent sanctuary known as "Baghdad's front door."
Col. Wayne Grigsby said Monday that his soldiers are "kicking the extremists' butt" in the Mada'in Qada region east of Baghdad. Homicides and kidnappings have dropped in the area since they increased the number of troops last spring from 72 to 3,500.
"We live in the towns with the people that we are here to help," Grigsby said, explaining that the improved security has lured contractors who have revived the marketplace and built a clinic, roads and water-pumping stations.
Also, Grigsby said, more than 6,000 Sunni tribesmen have been enlisted into concerned local citizens' brigades called "Sons of Iraq" units. The units have helped quell the Sunni extremism in the area, he said.
Prospects for peace seemed dimmer in northern Iraq, as the Islamic State of Iraq -- an umbrella group led by al Qaeda in Iraq -- announced over the weekend it is launching an offensive in Nineveh province.
The group says it wants to counter an operation by the Iraqi military, which is trying to clear the area of Islamic militants. A U.S. military source said more Iraqi troops will be moving into Nineveh province over the next few days to prepare for additional operations.
Iraqi Prime Minister Nuri al-Maliki traveled to the provincial capital of Mosul on Saturday to discuss strategy with top U.S. and Iraqi commanders. Last month, al-Maliki announced Iraq was moving forces into Mosul for a "decisive" battle.
Islamic State of Iraq announced its "revenge conquest" on a Web site over the weekend. It called for volunteers to perpetrate suicide attacks "against the crusader occupier in general and the Rafidha specifically." Islamic State of Iraq refers to Shiites as "Rafidha."
"Everybody knows of the enormity of the conspiracy against the people of Mosul led by the occupiers and the Rafidha and others with them from Baghdad and even from within," the statement said.
Al-Maliki says the Nineveh fight "will wipe out terror, criminal gangs and outlaws in the province." He also promised a beefed-up security initiative in Mosul, similar to the crackdown in Baghdad that began last year.
The effort in Mosul is part of Operation Iron Harvest, the U.S.-led offensive in Nineveh, Diyala, Tameem and Salaheddin provinces that kicked off last month.
Provinces neighboring Nineveh have stepped up security, putting authorities on high alert and setting up checkpoints, police said. Interior Ministry spokesman Maj. Gen. Abdul Karim Khalaf said there is a "big job" ahead in Mosul, and an operation will be launched in coming weeks.
Insurgents have frequently crossed into Mosul from Syria, making it a hotbed of fighting. Last month, a deadly blast at a residential building and an attack the next day that killed the head of Nineveh's police prompted Iraqi officials to focus on the city.
In other developments:
• Turkish warplanes bombed two deserted villages Monday in northern Iraq near where the borders of Iraq, Iran and Turkey meet, a Turkish military statement said. There were no casualties in Monday's shelling, which lasted about 12 hours. The Turkish military said it shelled 70 targets in Avashin, Basyan and Hakurk that belonged to the Kurdistan Workers Party, or PKK, which has been launching attacks against Turkey from Iraq.
• A roadside bomb struck an Iraqi police patrol Monday, wounding at least two police officers and two other people in northern Baghdad's mostly Sunni district of Adhamiya, according to an Interior Ministry official.
• Iraq and the United States will begin talks this month to establish a long-term relationship between the two countries, an Iraqi official said Monday. The talks are scheduled to begin the third week of February. The meetings will focus on security, politics and the economy, government spokesman Ali al-Dabbagh said. The final agreement will replace a U.N. mandate that expires in December.
• On Sunday morning, an Interior Ministry official was killed when a bomb attached to his car exploded in western Baghdad. Lt. Col. Mohammed Ibrahim worked in National Police Affairs, an official with the ministry said.
• Four members of a neighborhood watch group were found shot to death in a house north of the Iraqi capital, officials said. The U.S. military confirmed Sunday the death of four young men who were part of a "concerned local citizens" group in Diyala province. The men were 17, 18, 20 and 21 years of age. E-mail to a friend
CNN's Cal Perry, Jomana Karadsheh and Yousif Bassil contributed to this report.