President Trump announced Tuesday that he is issuing an executive order that will temporarily suspend some kinds of immigration to the U.S. for 60 days.

Details: The order will only apply to individuals seeking permanent residency. "In other words, those receiving green cards,” Trump said. It will not apply to those entering the U.S. on a temporary basis.

After the 60-day period, the administration will reevaluate whether to extend or modify the order.

Trump did not provide any further details on whether there would be other exemptions and noted that the order was still being written.

What he's saying: "By pausing immigration, we will help unemployed Americans be first in line for jobs as America reopens. So important," Trump said Tuesday.

"It would be wrong and unjust for Americans laid off by the virus to be replaced with new immigrant labor flown in from abroad. We must first take care of the American worker, take care of the American worker."

What they're saying: Trump's announcement, first previewed in a vague tweet on Monday night, caught many administration officials, members of Congress and immigration restrictionists by surprise.

Top House and Senate leaders, both Democrat and Republican, told Axios the first they heard of the planned order was from Trump’s tweet. Their offices scrambled Tuesday to get more information.

"We should've been made aware of this, but we weren't," a senior GOP congressional aide told Axios. "None of us got a heads up."

Between the lines: Immigration hardliners told Axios they had expected the order to be more wide-ranging — impacting people coming into the U.S. on some short-term work visas like H-1B and H-2B visas.

"Temporary workers are the ones who displace Americans. If you don’t do that you’re not doing anything," said Ryan Girdusky, a conservative writer who has pushed for more restricting immigration to the U.S.

Thomas Homan, former head of Immigration and Customs Enforcement (ICE), told Axios that “it makes sense to protect opportunities for our workforce while this pandemic plays out.” He said he wanted to wait and see the final details in the order itself to determine whether it does enough for American workers.

Don't forget: Much of the immigration system has already halted because of the coronavirus outbreak.