Prime Minister Stephen Harper greets NATO Secretary General Jaap de Hoop Scheffer on Parliament Hill on Thursday. ((Jonathan Hayward/Canadian Press))

Despite mounting Canadian casualties, NATO's secretary general urged Canadato continue its military mission in Afghanistan past its 2009 withdrawal deadline.

"I think more time is necessary to create those conditions for reconstruction and development to go on," said Jaap de Hoop Scheffer, who visited Montreal Thursday.

The visit by de Hoop Scheffercame a day after three Canadian soldiers were killed in Afghanistan and the same daya poll was released suggesting 70 per cent of Quebecersoppose the Afghan mission.

"I know how dramatic it is if Canadian soldiers pay the highest price," de Hoop Scheffer said an economic conference in Montreal. "But I still say, you are there for a good cause."

De Hoop Scheffersaid he wanted Quebecers to understand the importance of the Afghan mission.

"Please do realize in a nation like Canada, with such an enormous tradition of peacekeeping in the framework of the United Nations … [that] helping Afghanistan, participating in what is the threat of a global form of terrorism, making reconstruction possible — you are there for a good cause," he said.

Defending "basic values" such as democracy, the rule of law and independence of the media are paramount concerns,de Hoop Scheffer said, and Canadians should remember that NATO is "still supported by the large majority of the Afghan people."

Getting the alliance of 26 nations to stay the course in Afghanistan "is a message to the Canadians as much as it is to the Dutch or to the Danes or to the Norwegians," he said. "It's a message I have for all of my allied friends in the alliance and the partners alike."

De Hoop Scheffer's pitch comes as the federal government has been underpressurein the House of Commonsto definethe lengthof Canada'scommitmentto the mission and make its intentions in Afghanistan clear.

In a number of speeches and public comments, both Prime Minister Stephen Harper and Defence Minister Gordon O'Connor have signalled Canada is willing to consider an extended commitment. But they have said no final decision has been made and Parliament will have an opportunity to debate an extension.

The Valcartier base is expected to send 2,000 soldiers to Afghanistan this summer.To date,60 Canadian soldiers have been killed in Afghanistan.

De Hoop Schefferlater met with Harper in Ottawa.

With files from the Canadian Press