KABUL (Reuters) - Six Canadian soldiers were killed in southern Afghanistan on Sunday when their vehicle was blown up by a roadside bomb, a coalition spokesman said. At least two soldiers were injured.

It was the worst single incident for the 33,000-strong NATO multinational force fighting Taliban insurgents in several months.

"I can confirm they are Canadian but the identities have not been released," Lt. Morgan Bailey said from Canada's capital, Ottawa.

The Canadian defence ministry later said on its Web site the incident happened west of Kandahar city, in the heartland of support for the Taliban. Canada's main base is in Kandahar.

Earlier in the day, one NATO soldier was killed and another injured by a similar bomb in another part of the volatile south, a NATO spokeswoman said. She did not say where the second attack took place.