Air Canada dropped as much as 6.2 per cent, the most since Dec. 21, as the Canadian government considers tougher measures to limit travel into the country because of new variants of COVID-19.

Prime Minister Justin Trudeau and members of his cabinet have talked openly about tightening rules to discourage international trips. The country requires anyone boarding a flight to Canada to have a negative virus test, and most are also required to quarantine for 14 days when they arrive. Those measures have not stopped some Canadians from making winter trips to warmer destinations where travel isn’t as restricted.

Deputy Prime Minister Chrystia Freeland reinforced the warnings against international flights at a news conference Monday.

“I can’t emphasize too much how important that is for all of us just to stay home,” she said. “As for additional border measures, those are actively being considered.”

Shares of Montreal-based Air Canada fell 4.4 per cent to $21.12 at 2:24 p.m. in Toronto, the biggest decline on the six-member Bloomberg Americas Airlines Index. Airline stocks are broadly down on concern about the spread of new, more contagious variants of the virus.