NATO chief Anders Fogh Rasmussen spoke Thursday at a Canadian development project in Kandahar. (CBC)

Canada should keep its troops in Afghanistan beyond 2011, NATO's new secretary general says.

Anders Fogh Rasmussen made the remark Thursday while visiting a Canadian development project in Kandahar province. Canada is expected to end its military mission in the country in just 18 months.

"Of course I’m not going to interfere with the domestic politics in individual allied nations, but seen from an alliance point of view, I would strongly regret if that became the final outcome of the Canadian considerations," he told CBC News.

"I would like to take this opportunity to express my strong appreciation of the significant Canadian contribution to our mission in Afghanistan.

"At the end of the day, it is a question of our own security. We cannot allow Afghanistan, once again, to become a safe haven for terrorists. And I also think it is in Canada’s interest to ensure a peaceful and stable Afghanistan."

Fogh Rasmussen's comments follow a pledge he made earlier that the alliance will remain in Afghanistan, despite flagging support in many nations over rising deaths among Afghan civilians and Western military personnel.

He flew to Kabul Wednesday to meet with politicians and military leaders, two days after taking control of the NATO alliance, which is struggling to maintain its cohesion as it battles Taliban insurgents thousands of kilometres from Europe.

"I can assure you and the Afghan people that we will stay and support you for as long as it takes to finish our job," the former Danish prime minister told Afghan President Hamid Karzai at a joint press conference in the capital.

Some 65,000 troops from 42 nations serve in a NATO-led force hobbled by disagreements over the need for more troops and widely divergent national restrictions on when troops can fight.

Recent polls show majorities in Britain, Germany and Canada oppose sending more troops to Afghanistan, even as President Barack Obama moves in more U.S. forces.

July was the bloodiest month for the U.S. and NATO in the nearly eight-year war, and the UN says civilian deaths soared by 24 per cent in the first half of 2009.