TORONTO (AP) — Canadian Prime Minister Justin Trudeau said Monday he will close the country’s borders to anyone not a citizen, an American or a permanent resident and asked all Canadians to say home amid the coronavirus pandemic.

“All Canadians as much as possible should stay home,” Trudeau said said outside his residence, where is self isolating after his wife tested positive for the virus.

Trudeau said his government based its decisions on science and public health recommendations, but said Americans would exempted despite cases surging in the U.S.

“We recognize that the level of integration of our two economies,” he said.

The U.S. is by far Canada’s largest trading partner — accounting for 75 percent of the country’s exports. Trudeau has spoken to U.S. President Donald Trump in recent days.

Trudeau also said his government will restrict flights to Canada to airports in four major cities. The Canadian government is also mandating air carriers to screen passengers with symptoms of the novel coronavirus out of lines so they don’t board planes home.

He said the country is taking “increasingly aggressive steps” to keep everyone safe.