WASHINGTON (AP) — President Donald Trump said that he will sign an executive order “to temporarily suspend immigration into the United States” because of the coronavirus.

“In light of the attack from the Invisible Enemy, as well as the need to protect the jobs of our GREAT American Citizens, I will be signing an Executive Order to temporarily suspend immigration into the United States!” Trump tweeted late Monday.

He offered no details about which immigration programs might be affected by the order.

National security adviser Robert O'Brien on Tuesday cast the president's announcement as a move to protect the American people's health. O'Brien said the temporary halt to immigration would not be “dissimilar” to limits on travel to the U.S. from China that Trump put in place in January.

“We're trying to do everything, the president's trying to do everything he can to put the health of the American people first during this crisis,” O'Brien said on Fox News Channel. “So this is one step. It's not dissimilar to the restrictions on travel from China that he implemented back on Jan. 29 at the very outset of this public health crisis.”

O'Brien said the administration believes those travel restrictions saved lives.

Asked about Trump's reference to jobs, O'Brien referenced the virus' economic toll.

“There’s been an economic cost here, too, and the president’s looking out for Americans on both fronts at every turn,” he said.

Trump has taken credit for his restrictions on travel to the U.S. from China and hard-hit European countries, arguing the restrictions contributed to slowing the spread of the virus in the U.S. But he has not extended those restrictions to other nations now experiencing virus outbreaks.

Due to the pandemic, almost all visa processing by the State Department, including immigrant visas, has been suspended for weeks.

Almost 800,000 Americans have come down with COVID-19, the disease caused by the coronavirus, and more than 42,000 have died, according to figures compiled by Johns Hopkins University.