Sept. 19 (Bloomberg) -- NATO is investigating after a district governor in southern Afghanistan was killed in a possible ``friendly fire'' incident involving Australian troops.

The shooting took place in Tarin Kowt in Uruzgan province after special forces soldiers came under fire while on foot patrol, Australia's Department of Defence said today.

Troops returned fire in ``self-defense'' and Rozi Khan, the governor of Chora district, was among those killed, the department said in a statement. It remains unclear whether the tribal leader was killed by Australian forces, and NATO and the Afghan government are investigating, it said.

Australia has about 1,000 military personnel stationed in Uruzgan province and around Kandahar Airport as it takes part in the NATO-led campaign against the Taliban insurgency. Almost seven years after it was driven from power by a U.S.-led coalition, the Islamist movement has stepped up its offensive in a bid to topple President Hamid Karzai's government.

The firefight, which took place late Sept. 17 or early yesterday, may also have left three Afghan police officers dead and two injured, NATO's International Security Assistance Force said in a statement. No Australian soldiers were wounded.

NATO, Afghan Probe

Afghanistan's Interior Ministry and ISAF ``have agreed to jointly investigate the exact circumstances of the incident and will report their findings when they are available,'' the NATO- led force said.

The Australian patrol was fired on ``from a number of locations by unknown attackers,'' the defense department said in the statement. An initial assessment indicates the troops ``acted in accordance with their rules of engagement and that their actions were appropriate and proportionate in what was a complex and lethal environment.''

Karzai expressed sorrow over the governor's death and said it was the result of a ``misunderstanding between international forces and local troops,'' Agence France-Presse reported.

The governor had gone to help a friend who believed his home was surrounded by Taliban fighters, according to the report. The forces outside the man's house were actually international soldiers, who in turn mistook Khan and his men for insurgents, AFP said, citing a local police commander.

Karzai's government has called on international forces in Afghanistan to show more restraint during operations against the Taliban following an increase in the number of civilians killed.

In the first eight months of this year, 1,445 civilians were killed in Afghanistan, either by international and Afghan forces or militants, an increase of 39 percent on the same period last year when 1,040 died, according to the United Nations.

The Taliban and other rebels were responsible for 800 deaths during the period, or 55 percent of the total. Among the 577 civilians killed by international forces or the Afghan National Army, more than two-thirds died in air strikes. Another 68 deaths, mostly from crossfire, couldn't be attributed to either side.

U.S. Army General David McKiernan, the commander of NATO forces in Afghanistan, earlier this month ordered troops to review when they use lethal force to avoid civilian casualties.

To contact the reporters on this story: Ed Johnson in Sydney at ejohnson28@bloomberg.net; Gemma Daley in Canberra at gdaley@bloomberg.net.

Last Updated: September 19, 2008 00:41 EDT