An investigation is underway after an Afghan man died, and another was injured in a shooting involving a Canadian convoy just outside Kandahar city on Thursday.
Military officials said a taxi had approached an International Security Assistance Force convoy and ignored visual warnings to stop.
Warning shots were fired and troops then carried on with their patrol, ISAF said in a written statement.
The two Afghan men in the taxi were seriously injured and treated at a hospital where one later died.
The other man was transferred to a medical unit at Kandahar Air Field where he underwent medical treatment. He is expected to be discharged shortly.
"We deeply regret the loss of innocent civilian lives and a full investigation is being carried out," said Wing Commander Antony McCord, an ISAF spokesman for Regional Command South.
"ISAF reserves the right to self defence, but every effort is made to avoid risk to civilian life while also dealing with the potential insurgent threat posed by vehicle born suicide bombers. Afghan citizens are urged to comply with the warning signs in order to prevent these incidents."
The Canadian military confirmed the incident but did not release a comment.
Canadian convoys are usually led by one vehicle that drives in the middle of a road and honks its horn to alert traffic to yield.
But convoys in Kandahar province, regularly dealing with ambushes and roadside bombs, have been involved in friendly fire.
On Oct.4, a convoy fired on a truck driving with its headlights off, which turned out to be an Afghan National Police patrol.
Later that evening, the convoy fired on another truck, which belonged to a private security company employed by other coalition countries based at Kandahar Airfield.
On Oct. 2, Canadian troops accidentally shot and killed an Afghan man and injured a young boy Tuesday in southern Afghanistan when they approached a Canadian re-supply convoy on a motorcycle in downtown Kandahar.
Another Afghan civilian was killed in late September and several others were injured in a road traffic accident involving Canadian troops in Kandahar.
"Afghan citizens are urged to comply with . . . warning signs in order to prevent these incidents," McCord said on Thursday.
During the summer, Afghan elders raised safety concerns about military convoys cutting through Kandahar city.
In response to the rising number of civilian casualties, Afghan National Police have suggested Canadian convoys share times and routes and be escorted by local authorities.