Liberal Leader Stéphane Dion, left, and deputy Liberal leader Michael Ignatieff speak to reporters during a scrum at the Kandahar Airfield in Afghanistan late Saturday. ((Tobi Cohen/Canadian Press))

As the federal Liberal leader was wrapping up a visit to Afghanistan on Sunday, a roadside bomb blast injured four Canadian soldiers in the dangerous Panjwaii district, military officials said.

The soldiers were working to clear a dirt road of mines when their vehicle struck the improvised explosive device (IED) at 2:15 p.m. local time.

The injured were brought by helicopter to the Canadian-run field hospital at Kandahar Airfield. The men were treated, and two were soon released. Two others were being held for observation, but it's expected they will be released on Monday.

The incident happened 35 kilometres southwest of Kandahar City near Zangabad town in Kandahar province.

The military would not release the names of the injured men, or their units or the type of vehicle they were using.

Earlier in the day, Opposition Leader Stéphane Dion paid a visit to Canadian troops stationed in Kandahar, a day after explaining to government officials his policy on getting Canada out of combat roles in the war-torn country once the country's mandate expires in February 2009. Dion said he favours Canada taking on a more diplomatic role.

Dion played a friendly game of hockey with the soldiers to end his unannounced visit that he and deputy Liberal leader Michael Ignatieff began in Kabul on Saturday.

The two politicians also toured a forward operating base in the Zhari region, where Canadian Forces soldiers are training their Afghan counterparts to fight the Taliban.

It was known they had travelled to Kabul, but the details of their trip to southern Afghanistan and their visit to the base were kept secret to protect them from attack.

But Helena Guergis, the Secretary of State for Foreign Affairs and International Trade, revealed in a Saturday statement criticizing Dion that he would be visiting the Canadian unit called the provincial reconstruction team, or PRT.

"I think he should apologize to our troops while he is touring the PRT in safety," she said.

The Liberal Party said in a statement Sunday that Guergis had effectively told "the murderous Taliban" about Dion's plans to visit the base, putting his life and the lives of Canadian soldiers and diplomats at risk.

A Guergis spokesperson said the minister didn't actually know Dion would visit the base, but that she assumed he would because his visit to Afghanistan wouldn't be complete unless he did.  

Canada has about 2,500 troops stationed in southern Kandahar province, where Canadian soldiers have been regularly fighting the Taliban.

Dion and Ignatieff flew to the airfield Saturday night after spending the day in Kabul, where they met with Afghan President Hamid Karzai.

The Opposition leader said his first visit to the country hasn't changed his vision of what Canada's future role in there should be once its current mandate ends the province.

Security, not combat

"The military forces of Canada have a role to play after February 2009 — even though it's not combat, it will be for security," Dion told reporters Sunday.

He said it makes sense to support efforts to train Afghan security forces while emphasizing development and reconstruction, instead of maintaining the combat mission.

Dion said that while Canada should remain in Afghanistan beyond its current commitment, soldiers must focus more on things like women's rights, education and water management.

Both Dion and Ignatieff said they learned during the two-day visit that the biggest successes are development projects led by the Afghans themselves.

Their visit came just a week after the Liberal party submitted its recommendations on the future of the Afghan mission.

A panel studying Canada's role in Afghanistan is expected to report back to the government by the end of the month.

While the Conservatives favour extending the current mission, the Liberals are promoting a revised role that will see Canadian soldiers removed from Kandahar.