Four Canadian soldiers, along with a Canadian reporter, were killed Wednesday by a powerful improvised explosive device on the outskirts of Kandahar city in Afghanistan.

The deaths occurred as they drove in an armoured vehicle through a part of the province that was generally considered safe, about four kilometres south of the city at about 4 p.m. local time.

Five others were injured, and were taken to hospital at Kandahar Airfield.

The Department of National Defence has not released the names of the soldiers as there were problems notifying all the next-of-kin.

Calgary Herald reporter Michelle Lang, 34, has been identified as the journalist killed.

"Yesterday, Canada lost five citizens," Brig.-Gen. Daniel Menard, commander of coalition forces in Kandahar, said early Thursday. "The soldiers were conducting a community security patrol in order to gather information on the pattern of life and maintain security in the area."

"The journalist was travelling with (the troops) to tell the story of what Canada's soldiers are doing in Afghanistan," Menard said.

Lang had just been in Afghanistan for a little more than two weeks for an assignment for Canwest News Service. It was her first assignment in the country.

In total, 138 Canadian soldiers have now been killed while serving in Canada's mission in Afghanistan which began in 2002. After almost eight weeks without a fatality, five soldiers have been killed in the last week.

Lang's first article from Kandahar was published on Dec. 20, 2009, with her last article posted on the Calgary Herald's website on Tuesday.

She was due to return to Calgary on Jan. 22, the Calgary Herald said.

Lang joined the Calgary Herald in 2002, after reporting at the Regina Leader-Post. She won a National Newspaper Award in 2008 for her health care reporting.

She recently became engaged to her boyfriend, Michael Louie, and they were to be married in July. She was born in Vancouver.

Lang was the first Canadian journalist killed in Afghanistan and her colleagues expressed their sorrow Wednesday night.

"Michelle was one of those people that really lit up the room," Calgary Herald editor-in-chief Lorne Motley told CTV News Channel Wednesday night. "She was always willing to go the extra mile, whether it was giving to others, to whether it was covering a story."

"We are all devastated by the loss of Michelle and our thoughts right now are with her family and her fiance," Scott Anderson, editor-in-chief of Canwest News Service, told the Calgary Herald. "Journalists need to -- and do -- put themselves at risk every day to report first-hand on important stories like Afghanistan. But that doesn't make this any easier.'

Prime Minister Stephen Harper's press secretary, Dimitri Soudas, issued a statement on his behalf Wednesday night.

"On behalf of all Canadians, the prime minister offers his most sincere condolences to the loved ones of those who lost their lives in Afghanistan earlier today," the statement said.

"Four brave soldiers paid the ultimate price while courageously serving their country in Kandahar. They perished seeking to help the Afghans build a better future for themselves while working tirelessly to advance Canadian values. Their sacrifice will not be forgotten.

"Also fallen is a brave reporter, Michelle Lang, who lost her life reporting on the invaluable work being done by Canadian soldiers, aid workers and diplomats in Afghanistan. Her unforeseen and tragic death will be felt in Calgary and in communities across Canada."

The prime minister will be issuing a statement once all the soldiers' families have been notified.

First trip 'outside the wire'

Colin Perkel, a reporter with The Canadian Press in Afghanistan, described the bombing as "in a single word, stunning."

"It came in a relatively safe area, on a routine patrol, just one of those things and out of the blue," he told CTV News Channel by phone. "Everybody is quite shocked by what has happened."

The bombing occurred in a part of the city that lies just down the road from Dand district, Perkel said, which houses one of the "model villages" that Canadian troops have been focusing on.

It was Lang's first trip "outside of the wire" after spending several days touring bases with Chief of Defence Staff Walter Natynczyk.

"I've seen a lot of reporters come here who seem like action junkies or kind of 'Hey, look at me, I'm in Afghanistan'," James Murray, a CBC reporter who has spent the past six of seven months in Kandahar, told The Canadian Press.

"She was the kind of journalist you would want to have here. She was kind and decent, and curious."

Retired major general Lewis Mackenzie said the attack was likely planned to coincide with the holiday season in Canada.

"The Taliban aren't stupid, even though it's not a homogenous organization. They know very well that the psychological impact on... the Canadian public, is much more dramatic during this holiday season that we are privileged to enjoy," MacKenzie told CTV News Channel. "It's disappointing to the extreme and it's absolutely horrifying to the loved ones of the deceased."