The U.S. and Mexico have agreed to restrict all non-essential travel across their border, the Trump administration announced Friday.
Members of the White House coronavirus task force also said that people who enter the country from Mexico and Canada without proper documentation will be immediately turned away from the United States' borders.
The announcement came two days after President Donald Trump and Canadian Prime Minister Justin Trudeau said that the U.S.-Canada border would be closed to non-essential traffic due to the coronavirus pandemic.
Neither of those travel restrictions will apply to trade, or workers involved in so-called essential work. Both agreements will go into effect Saturday.
The decision to suspend entry into the U.S. for people seeking to cross the border "illegally" was made "because of the public health threat that their entry into the United States represents," Health and Human Services Secretary Alex Azar said.
The Trump administration has previously taken aggressive steps to stem the flow of migrants entering the U.S. illegally.
"Today's announcement is just the latest in a long line of bold, decisive actions the president has taken to protect Americans from the coronavirus spreading across our borders," Azar said.
The White House briefing came as U.S. officials at every level of government took unprecedented steps to try to slow the spread of the virus and soften its devastating economic impact.
Treasury Secretary Steven Mnuchin announced earlier Friday that the IRS will delay the national income tax filing deadline by three months, pushing it back to July 15. That measure was included as part of the Senate's coronavirus economic stimulus bill, which is expected to cost at least $1 trillion and is currently being negotiated on Capitol Hill.
At the state level, Democratic Gov. Gavin Newsom of California issued a sweeping order for all residents to stay at home and closing dine-in restaurants, bars and clubs, gyms and fitness studios.
New York Gov. Andrew Cuomo followed suit Friday morning, ordering all non-essential businesses to keep 100% of their workforce at home.
The COVID-19 virus, believed to have originated in the Chinese city of Wuhan, has infected more than 245,000 people around the world, killing more than 10,000, data from Johns Hopkins University shows. In the U.S., at least 14,250 people have contracted the virus and more than 200 have died, according to Johns Hopkins.