Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

WASHINGTON — President Donald Trump announced Wednesday that the U.S. and Canada had agreed to close their border to all “nonessential traffic" because of the spread of the coronavirus.

Trump indicated in his announcement on Twitter that it will not affect trade between the two countries but did not offer any additional details.

Download the NBC News app for full coverage of the coronavirus outbreak

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

“We will be, by mutual consent, temporarily closing our Northern Border with Canada to non-essential traffic. Trade will not be affected. Details to follow!” Trump tweeted.

The president has not closed the border with Mexico.

Trump announced last week that the U.S. would ban foreign travelers from Europe for the next 30 days. A few days later, the administration announced that the travel restrictions would be extended to foreigners traveling from the United Kingdom and Ireland as well.

Trump announced earlier Wednesday that he plans to hold a news conference Wednesday on a development regarding the FDA and the coronavirus.

There has not yet been an announcement from the Canadian government about the border closing.

Asked by reporters Tuesday if he planned to shut the land borders to the U.S., Trump said he did not want to shut them, but was "discussing" the issue with Mexico and Canada.

A senior administration official told NBC News that the administration has already explored the possibility of new restrictions on the southern U.S. border, because of fears that once the virus hits Central American countries like Honduras, Guatemala and El Salvador, citizens of those countries will begin to travel to the U.S. border in large numbers to try to access the U.S. healthcare system.

One option that has been under consideration, said the official, is invoking 42 USC 265, a portion of the federal legal code that says the U.S. surgeon general “shall have the power to prohibit, in whole or in part, the introduction of persons and property from such countries or places as he shall designate in order to avert such danger, and for such period of time as he may deem necessary for such purpose.”