OTTAWA -- Prime Minister Justin Trudeau is urging Canadians abroad to come home while they still can, as Canada is shutting the border to non-Canadian citizens, with limited exceptions to limit the spread of COVID-19.

Permanent Canadian residents, the immediate family members of Canadian citizens, diplomats, air crews, and U.S. citizens are still being allowed into Canada at this time.

"If you're abroad, it's time for you to come home. If you've just arrived, you must self-isolate for 14 days, and finally all Canadians as much as possible, should stay home," Trudeau said.

Anyone who has symptoms of COVID-19 will not be able to enter Canada. Air operators are being instructed to prevent any traveller who presents symptoms of the virus from boarding a plane.

"I know this news will spark concern," Trudeau said to Canadians who are currently out of the country.

"It's time to take every precaution to keep people safe," Trudeau said, adding that additional measures should be expected as soon as tomorrow.

The prime minister said the government will support Canadians currently abroad through a program that will see them either cover the costs to get them home, or cover their basic needs while they wait to return.

He addressed the nation from self-isolation at Rideau Cottage, updating Canadians on the measures being taken to combat the spread of the COVID-19 pandemic.

Trudeau said the virus has been spreading quickly across the world, and Canada is no exception. Therefore, Canada is taking “increasingly aggressive steps” to keep Canadians safe.

Trudeau announced additional flight restrictions effective Wednesday, that will see some international flights rerouted to Montreal, Toronto, Calgary or Vancouver for dedicated enhanced screening.

The prime minister said these border restrictions will not apply to commerce or trade.

“I know that these measures are far-reaching. They are exceptional circumstances, calling for exceptional measures,” Trudeau said.

He said that while it will be an adjustment, all Canadians should stay home if they can, to do their part to limit the virus from spreading and hopefully avoiding an overburdening of the Canadian health-care system.

With schools, community centres and businesses shutting their doors in an effort to help contain the novel coronavirus, many Canadians are spending the day indoors, social distancing or self-isolating.

Throughout the day provincial governments and health authorities have been providing updates on the number of cases in their provinces, with some premiers calling for more action from the federal government, including tightening up the borders.

The prime minister has been self-isolating since Thursday, when his wife Sophie was confirmed to have contracted the virus. On Monday morning, Trudeau spoke with fellow G7 leaders, where he likely informed them that all foreign nationals will not be able to enter Canada.

Several top cabinet ministers are holding a media availability on Parliament Hill, where the details of the latest measures are being discussed.

Deputy Prime Minister Chrystia Freeland, Health Minister Patty Hajdu, Treasury Board President Jean-Yves Duclos, Public Safety and Emergency Preparedness Minister Bill Blair, Transport Minister Marc Garneau, and Chief Public Health Officer of Canada Dr. Theresa Tam are speaking from the National Press Theatre.

Going forward, there will be a daily update from Health Canada officials, at noon.

Trudeau chaired a federal cabinet meeting from his own self-isolation on Sunday. Before the meeting, he told CTV's Question Period that all options for further measures were on the table and being discussed. He also committed that additional measures to support families and workers would be coming.

Last week, Parliament suspended sitting for five weeks and the Liberals rolled out a $1-billion health and economic response package, as well as an additional $10 billion for businesses who are being impacted by the virus and consumers' changing habits.

When Trudeau began speaking, there were 377 reported cases in Canada. That number rose to 416 an hour and a half later.

Trudeau said that to date public health authorities have administered more than 25,000 COVID-19 tests.