President Donald Trump has said he will sign an executive order to temporarily suspend all immigration to the US to fight the coronavirus.
In a late night message on Twitter, he cited "the attack from the invisible enemy", as he calls the virus, and "the need to protect the jobs" of Americans.
He gave no other details. Critics say the Trump administration is using the pandemic to crack down on immigration.
The country has 782,159 confirmed cases of Covid-19 and 41,816 deaths.
Mr Trump's announcement comes as the White House also argues the worst of the pandemic is over and the country can begin reopening.
The US has already agreed with both Canada and Mexico to extend border restrictions on non-essential travel until at least mid-May.
Travel has also been sharply restricted from Europe and China, though people with temporary work visas, students and business travellers are exempted.