[David]

The Associated Press

KANDAHAR, Afghanistan - U.S. warplanes fired on Canadian troops fighting Taliban forces Monday in southern Afghanistan, killing one soldier and wounding five in an attack 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 outbreak of violence since U.S.-led forces toppled the 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.

"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.

U.S. 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.

The five wounded soldiers were evacuated out of Afghanistan for medical treatment, said NATO spokesman Maj. Scott Lundy. An investigation has been launched.