KANDAHAR, Afghanistan (AP) - U.S. warplanes mistakenly fired on Canadian troops fighting Taliban forces yesterday in southern Afghanistan, killing one soldier and wounding five in an operation that NATO said also has left 200 insurgents dead.

A British soldier attached to NATO and four Afghans also were killed in a suicide vehicle bombing Monday in Kabul, while 16 suspected Taliban militants and five Afghan police were killed elsewhere in the country.

The intense fighting comes amid Afghanistan's deadliest spate of violence since U.S.-led forces toppled the hard-line Taliban regime for hosting al-Qaida leader Osama bin Laden after the Sept. 11 attacks.

It also underscored the increased danger to NATO-led multinational forces since they took over control of security in the volatile south from the U.S.-led coalition last month.

Five Canadian soldiers have been killed since an anti-Taliban operation was launched Saturday in southern Kandahar province's Panjwayi district, long a hotbed of insurgent activity. Some 32 Canadian soldiers have been killed in Afghanistan since 2002.

"It is particularly distressing to us all when, despite the care and precautions that are always applied, a tragedy like this happens," said NATO commander Lt. Gen. David Richards.

The "friendly fire" incident happened after ground troops battling Taliban militants requested air support, NATO said.

NATO said the International Security Assistance Force provided the support but "regrettably engaged friendly forces during a strafing run, using cannons." It later identified the planes as U.S. A-10 Thunderbolts.

American military spokesman Sgt. Chris Miller confirmed that U.S. planes were involved and said the NATO force can request air support from the U.S.-led coalition.

One Canadian soldier was killed, and five soldiers were wounded and evacuated out of Afghanistan for medical treatment, said NATO spokesman Maj. Scott Lundy. An investigation has been launched.

Meanwhile, a senior British officer said the crew of a British military plane that went down in Afghanistan on Saturday, killing 14, had reported a fire onboard shortly before the crash.

Chief of the Defense Staff Air Chief Marshal Sir Glen Torpy told Britain's Channel 4 News it was possible but unlikely that a Taliban missile had hit the disabled plane as it flew at low altitude. A purported Taliban spokesman had claimed responsibility.

In Kabul, suicide bomber detonated his explosives-laden four-wheel drive alongside a British armored military vehicle, killing a British soldier and four Afghans and wounding three other NATO soldiers, according to British and Afghan officials.