Prime Minister Stephen Harper visited troops on the front lines in Afghanistan and hinted that Canadian soldiers will be there past 2009.

"You know that your work is not complete," Harper told the assembled troops at a ball-hockey rink at the Kandahar airfield on Wednesday.

"You know we just can't put down our weapons and hope for peace. You know that we can't set arbitrary deadlines and simply wish for the best," he said.

The Liberals favour ending Canada's combat role in 2009 and the NDP want the combat mission ended immediately.

Soldiers defended their presence in the country. They have been in Kandahar province since February 2006.

"I feel we are making an incredible difference. You know, just seeing kids on the street waving to us," said Sapper Noah Starr.

"It's horrible that we are suffering casualties but it's part of being at war," said Master Cpl. Mark Cavers.

In Ottawa, Liberal defence critic MP Denis Coderre, issued a statement saying he was "deeply troubled that Mr. Harper continues to support an open-ended counter-insurgency mission in Kandahar."

Brig.-Gen. Tim Grant, Canada's senior military commander in Afghanistan, said there is contingency planning that extends past February 2009.

"The work will not be done here in February 2009, so we want to make sure we do as much as we possibly can between now and then," Grant said. "But at the same time, it would be irresponsible of us not to plan past that point, for the good of the country."

Some have said a proper counter-insurgency mission could take 10 years or more.

Later that day, Harper went to the forward operating base at Ma'sum Ghar.

Pooled video tape -- the prime minister's office rejected a plan by the military to have reporters record the trip -- showed Harper at a lookout point flanked by soldiers.

Ma'sum Ghar is where Pte. Mark Anthony Graham died and 30 other soldiers were injured when a pair of U.S. A-10 Thunderbolts strafed them during a major combat operation.

Col. Mike Cessford, the deputy commander of the Canadian contingent in Kandahar, told reporters that Harper's visit there would have "absolute not" been possible a year ago.

"I have a doctorate in history," Cessford told a news conference before Harper left.
 
"No sitting prime minister, in my opinion, has been closer to combat operations than this prime minister today."

Harper had lunch with an infantry company and spoke to Afghan army commanders working alongside the 150 Canadians stationed at the base.

"This is the Taliban heartland outside of Kandahar, about 25 kilometres southwest of the city," CTV's Beijing Bureau Chief Steve Chao reported from Kandahar.

"Occasionally, Ma'sum Ghar still gets rocketed -- an interpreter lost his life there last week during a rocket attack -- despite this, Prime Minister Harper said he felt he needed to go down there personally to see the front lines."

Harper kicked off his two-day visit Tuesday, appearing beside Afghanistan's President Hamid Karzai for a news conference in Kabul. He is on his way back to Canada.

With a report from CTV's Robert Fife and files from CTV's Steve Chao and The Canadian Press