Prime Minister Justin Trudeau has announced several tough new measures to curb the spread of COVID-19 variants through international travel.

Starting Sunday, Ottawa and Canada’s major airlines have agreed to cancel all flights to “sun” destinations—the Caribbean and Mexico—through April 30. Airlines Sunwing, WestJet, Air Canada, and Air Transat will work with people who are currently abroad to organize return flights.

As of next week, all international flights will only be able to land in Toronto, Calgary, Montreal, and Vancouver.

In addition to pre-boarding tests, Canada will mandate PCR COVID testing at the airport for people returning to Canada. Travellers will then have to wait up to three days at an approved hotel for their test results at their own expense, which Trudeau said is expected to be more than $2,000.

Travellers must also pay for their own COVID-19 tests at the airport. The testing will be privately administered so as not to use up public testing resources, Trudeau said.

Travellers with negative test results will continue quarantining at home under “significantly increased surveillance” and enforcement.

People who test positive will then move to a “designated government facility” to make sure they are not carrying variants to finish their 14-day quarantine.

Canada will also require negative COVID tests for all non-essential travellers entering at land board with U.S.

Canada banned non-essential international travellers from entering the country last March. As of January 7, airline travellers must show proof of a negative COVID-19 test within 72 hours of their departure time.

Trudeau said today that fewer than two percent of COVID cases are linked to Canadians coming back to the country from abroad.

However, the spread of highly transmissible new virus variants from the U.K., South Africa, and Brazil led the government to strengthen international travel restrictions, he added.

“We saw that one travel case resulted in many, many cases in and around Barrie,” Trudeau said. “One case of the variant that comes in could cause significant challenges. That’s why we need to take extra measures.”

As of January 28, there have been 51 confirmed cases of the B117, the highly transmissible U.K. variant in Ontario.

Non-essential international travellers have been banned from entering Canada since last March. Anyone entering Canada from overseas must self-quarantine for two weeks. As of January 7, airline travellers must show proof of a negative COVID-19 test within 72 hours of their departure time.