Prime Minister Stephen Harper, who has committed to pulling out Canadian troops from Afghanistan in 2011, said on Thursday some other Western leaders wrongly believed NATO forces could stay there forever.

Canada has around 2,500 troops based in the southern city of Kandahar, in a region where the Taliban is strong. It has lost 97 soldiers and a diplomat since late 2002.

Harper initially said Canada would not leave Afghanistan until the country was able to cope for itself. Earlier this year, amid increasing public and political pressure, he agreed to bring the troops back by the end of 2011.

"I think that''s wise. One of the things I disagree with some other Western leaders is that our plan can be somehow to stay in Afghanistan militarily indefinitely," he said during a televised election campaign debate.

"If we are to truly pacify that country and see its evolution, we have to train the Afghan army and police so that they are credibly able to take greater responsibility for their own security ... we won''t achieve such a target unless we actually set a deadline and work to meet it."

Harper said he had made the same point to U.S. President George W. Bush as well as the two men vying to be his successor -- Republican John McCain and Democrat Barack Obama.

Polls show that Harper''s Conservatives are set to retain power in Canada''s Oct 14 election.

"2011 is three more years off. By then Canada will have been in Afghanistan for nearly 10 years ... we will have been in Kandahar for six years," he said.

"If we never leave, will the job ever get done?"