Petr David Josek, Associated Press
A U.S. soldier takes a rest Monday in the town of Owesap about 12 miles south of Baghdad. Most U.S. deaths this month have been in areas north of Baghdad.

BAGHDAD — Iraqi troops detained 43 people, most Sri Lankans and other foreigners, in a convoy run by a U.S.-contracted firm after an Iraqi woman was wounded in a Baghdad shooting involving their vehicles, the U.S. military said. It denied reports that two Americans were also arrested.

The incident follows a series of recent shootings in which foreign security guards have allegedly killed Iraqis. Last month, the Iraqi Cabinet sent parliament a bill to lift immunity for foreign private security companies that has been in effect since the U.S. occupation began in 2003.

The convoy belonged to Almco Group, an Iraqi-run company based in Dubai, United Arab Emirates, which has contracts with U.S.-led forces to provide food, water and other life-support functions to military transition teams, as well as the construction of a justice compound, Maj. Brad Leighton said.

But the military spokesman said it was not yet known if those detained were working on those contracts or under the auspices of a contract with another agency in Iraq.

"At this point we have not determined whether these individuals were acting on a U.S. contract at the time of this incident," Leighton said. "They may have been working for another contract at the time that they were detained."

Almco officials did not immediately respond to phone calls or e-mails seeking comment.

Brig. Gen. Qassim al-Moussawi, the chief Iraqi military spokesman in Baghdad, said the convoy was driving on the wrong side of the road in the central Baghdad neighborhood of Karradah when the woman was wounded in a shooting that took place about midday.

He said earlier those arrested included two American guards, along with 21 people from Sri Lanka, nine from Nepal and 10 Iraqis.

But Leighton denied any Americans were involved, saying the confusion may have stemmed from two Fijians who held identification cards issued by the U.S. Department of Defense.

Besides the Fijians, he said 21 Sri Lankans, nine Nepalese, one Indian and 10 Iraqis were being held at an Iraqi army headquarters and coalition forces were dispatched to stay with them to ensure they receive proper treatment.

Leighton confirmed a woman was wounded in a shooting involving the convoy, but he declined to give more details, saying the circumstances were still under investigation.

The role of private security guards has become particularly controversial following a Sept. 16 shooting in which Blackwater Worldwide guards killed 17 Iraqi civilians at Baghdad's Nisoor Square.

The FBI is continuing its investigation into the shootings, although the Iraqi government has concluded that the security guards were unprovoked when the began shooting at an intersection at Nisoor Square in western Baghdad. The North Carolina-based company, the largest private security firm protecting U.S. diplomats in Iraq, has said its security convoy was under attack before it opened fire.

The Iraqi Cabinet's initiative to lift immunity for private security companies would not be retroactive and therefore not affect the Blackwater employees who were involved in the Sept. 16 shooting. Parliament has yet to act on the measure.

"We have given orders to our security forces to immediately intervene in case they see any violations by security companies. The members of this security company wounded an innocent woman and they tried to escape the scene, but Iraq forces arrested them," al-Moussawi told The Associated Press in a telephone interview.

Leighton said Almco was not conducting personal security activities for the U.S., although its construction contract did specify that the company should provide all required security for transportation and shipment of personnel and equipment.

Almco provides services ranging from dining facilities to water treatment and fuel supply for about 17,000 people in military camps and various companies across Iraq, according to the company's Web site.

A top U.S. commander, meanwhile, said violence in northern Iraq has declined at a slower rate than it has in other regions, as al-Qaida and other militants move there to avoid coalition operations elsewhere.

As a result, the north is now more violent than other regions. Most of the 27 U.S. deaths this month were north of Baghdad.

Army Maj. Gen. Mark P. Hertling, who commands U.S. troops in the region, said al-Qaida cells still operate in all the key cities in the north.

"What you're seeing is the enemy shifting," he told Pentagon reporters in a video conference from Tikrit. "The attacks are still much higher than I would like here in the north but they are continuing to decrease in numbers and scale of attacks."

He said 900 roadside bombs were placed in his region last month, compared with 1,830 in June.

Sporadic violence nationwide left at least 22 people were killed or found dead Monday.

The deadliest attack occurred near the southern city of Basra when a rocket slammed into a house, killing five children and their mother, police said. Police said they believe the rocket was targeting the nearby airport, which is the headquarters of the British military in the area, but fell short.

British-led forces plan to hand over security responsibilities to Iraqis in the predominantly Shiite province in mid-December, saying the levels of violence have dropped despite fears of escalating rivalries between Shiite militia fighters battling for power.

In another mostly Shiite province, Qadisiyah, U.S. and Iraqi troops detained about 70 suspected extremists and seized weapons caches, Maj. Gen. Othman al-Ghanimy said.

In other developments:

Iraq's chief prosecutor said a trial would begin "within days" for two former Health Ministry officials accused of letting death squads use ambulances and government hospitals to carry out kidnappings and killings and siphoning millions of dollars to the Mahdi Army, a case that will test the government's commitment to crack down on Shiite militias.

• The head of Iraq's largest Shiite party, Abdul-Aziz al-Hakim, returned home from Iran after undergoing another round of chemotherapy there for lung cancer.

• U.S. Embassy spokesman Philip Reeker, said several Iranians who have been detained by U.S. forces in Iraq were being allowed family visits starting Monday.