KABUL, April 8: 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 one soldier was 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 Ottawa. “I don't have the specific details on the incident itself but they will be coming out shortly.”

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.

About 5,000 Nato and Afghan troops are engaged in a major offensive, Operation Achilles, in Helmand province in the south, the opium heartland of the world's biggest producer.

British and Canadian troops make up the bulk of coalition forces in the south of the country.

The latest deaths bring the Canadian toll to 51 since Ottawa sent troops to Afghanistan in 2002. Canada's main base is in the southern city of Kandahar.

Nato follows a practice of not disclosing the province where its casualties take place since this could identify the victims' nationality.

Last year saw the bloodiest fighting since Taliban insurgents were ousted in 2001, mainly in the rebels' southern heartland of Helmand and neighboring Kandahar province.

Almost all Nato's combat activities in Afghanistan are being conducted by US, British, Canadian and Dutch soldiers in the south and east, bordering Pakistan.

Britain has said it will send another 1,400 soldiers soon -- making its deployment in Afghanistan greater than in Iraq.

The United States has also committed an extra 3,200 soldiers.

The Nato-led International Security Assistance Force (ISAF) has nearly quadrupled within the last three years, largely as a result of U.S. and British reinforcements, and the transfer of U.S. troops from a separate US-led coalition to ISAF.---Reuters