British Prime Minister Gordon Brown has issued an ultimatum to the Afghan government: either get rid of corruption, or Britain will pull all its troops from the country.

In a speech Friday Brown said he will no longer "put the lives of British men and women in harm's way," in Afghanistan unless the government there takes action against corruption.

Public support for Britain's presence in the country has plummeted, especially in the last few weeks, CTV's London Bureau Chief Tom Kennedy reported.

Ninety three soldiers have died, with seven just last week. Five of them were shot by an Afghan police officer they were training.

Last week's corruption-marred presidential election and the rising number of casualties have led to increased pressure on Brown to justify Britain's mission in Afghanistan.

Brown said it is up to Afghan President Hamid Karzai to restore international confidence in his government.

"International support depends on the scale of his ambition and the degree of his achievement in five key areas: security, governance, reconciliation, economic development, and engagement with Afghanistan's neighbours," he said.

"If the government fails to meet these five tests, it will have not only failed its own people, it will have forfeited its right to international support."

Canada's military component in Afghanistan will end in 2011, and the Department of Defence said Friday that Canada has already begun preparing to pull 2,800 soldiers and equipment out of that country.

Defence Minister Peter MacKay has refused to rule out the possibility that some Canadian support troops might be kept in Afghanistan after the 2011 deadline.

NATO officials say dwindling public support could be detrimental to the efforts to get the country back on track.

"The clock in Afghanistan is clearly running against us," said German Gen. Egon Ramms, whose Allied Joint Forces Command oversees NATO's force in Afghanistan. "In the end, politicians will not go against their public opinion."

Afghanistan continues to be unstable. Five NATO staff members were recently killed in an attack at a guesthouse, and on Thursday, NATO said it had moved staff to safer accommodations temporarily.

Karzai continues to promise to clean up his government, but corruption runs deep. Bribes are a part of everyday life and the country is full of drug money from its rich poppy crops, which are used to make opium and heroin.

A March report by the U.S. Agency for International Development found that corruption had reached "an unprecedented scope in the country's history."

Last year, Transparency International, a non-governmental organization, ranked Afghanistan as fifth last on its corruption list. The lower the rank, the higher corruption among public officials and politicians is perceived.

Only Haiti, Iraq, Burma and Somalia ranked lower.

A spokesperson for Karzai said Afghanistan and the international community need to work together to fight the corruption.

"But fighting corruption requires closer and more effective co-operation between the government of Afghanistan and the international community," said Humayun Hamidzada.