Canada warned the United States on Wednesday that it would not be able to meet its prescription drug needs.

“To me it is a matter of common sense that Canada cannot be the drugstore of the United States. Neither American consumers nor Canadian suppliers should have any illusions otherwise,” Health Minister Ujjal Dosanjh said.

“It is difficult for me to conceive of how a small country like Canada could meet the prescription drug needs of approximately 280 million Americans without putting our own supply at serious risk,” he said in the prepared text of a speech he was giving at Harvard Medical School.

Several U.S. states and cities have sought to save money by buying less-expensive Canadian drugs, as have many Americans, notably seniors and those with limited health-care coverage.

The issue figured in the recent presidential election campaign, with Democratic challenger John Kerry calling for Canadian imports and President Bush saying he first wanted to make sure foreign drugs were safe.

Dosanjh said he saw no evidence of supply shortages in Canada, with annual Internet pharmacy sales appearing to have plateaued at about $600 million, but he said that Ottawa was monitoring the matter closely.