Brig Gen Daniel Menard, commander of coalition forces in Kandahar, on the attack
Four Canadian soldiers and a journalist have been killed in an attack in the southern Afghan province of Kandahar.
The Taliban has reportedly claimed responsibility for detonating the roadside bomb used in the attack.
The journalist has been identified as Michelle Lang, 34, from the Calgary Herald, who had just arrived on her first assignment in the country.
This has been the deadliest year for foreign troops since the 2001 invasion. Canada's toll stands at 32 for 2009.
It has lost 138 troops in total in the course of the war.
This is the bloodiest attack in a single incident for Canadian troops in Afghanistan this year.
Qari Mohammad Yusuf Ahmadi told the Associated Press the bomb had exploded close to a bridge in Kandahar province.
The armoured vehicle in which the group was travelling was touring local reconstruction projects.
Ms Lang was the third journalist to die in Afghanistan this year, Reuters news agency reports.
An award-winning health reporter, her colleagues at the newspaper were said to have been devastated by the news of her death.
Reporter Michelle Lang had recently arrived in Afghanistan
She was recently engaged to be married and described as bright, quick-witted and kind.
"We are all very saddened to hear this tragic news," Alberta Health Minister Ron Liepert said in a statement.
"Michelle covered health issues with professionalism, accuracy and thoroughness."
The BBC's Lee Carter, in Toronto, says the deaths will add to the conviction felt by many Canadians that the country has carried a disproportionate number of casualties, especially in comparison to some European Nato allies.
Canada has a 2,800-strong force in Afghanistan, but the deployment has become increasingly unpopular at home and the troops are scheduled to be withdrawn at the end of 2011.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.