Prime Minister Justin Trudeau significantly restricted the entry of non-residents into Canada to combat the spread of the coronavirus.

At a press conference Monday from his residence in Ottawa, where the leader remains in self isolation, Trudeau said the government will be denying entry into the country to all foreigners, except for Americans. The new measures come into effect on March 18.

Trudeau also announced additional procedures, including instructing airlines to prevent all travelers with symptoms of Covid-19 to board a plane. All international flights -- excepting those from Mexico, the Caribbean, and the U.S. -- will be restricted to only four airports throughout the country. Airlines will be allowed to land in Vancouver, Toronto, Montreal and Calgary international airports.

Trade and commerce won’t be impacted by the ban.

When asked why the U.S. was exempt from the ban, Trudeau said Canada and the U.S. are closely coordinating their responses to Covid 19 and have extremely integrated economies. Canada ships about three-quarters of its exports to the U.S.

“We recognize that the level of integration of our two economies and coordination over the past while puts the U.S. in a separate category from the rest of the world,” the prime minister told reporters.

The decision to shutter international air travel began with U.S. President Donald Trump’s decision to ban travelers from Europe for 30 days. European Commission President Ursula Von Der Leyen on Monday also proposed closing Europe’s borders to all non-essential travel to Europe.

Trudeau continues to govern from home after his wife Sophie Gregoire Trudeau tested positive with Covid 19.

This article was provided by Bloomberg News.