Asked during the same briefing if he was considering a broader ban or more targeted restrictions, Trump said: “We're looking at the whole thing,” and suggested the administration would offer recommendations soon.

Trump’s comments come after Sen. Lindsey Graham (R-S.C.), a close Trump ally, tweeted late Tuesday that it is “time to consider limiting or banning domestic and international air travel for next 30 days.”

Several governors have developed their own travel restrictions, including in Florida, Maryland, South Carolina and Texas, which have said that anyone coming in from New York, New Jersey or Connecticut must self-quarantine for 14 days.

And the CDC last weekend issued a travel advisory urging residents of those three states to refrain from nonessential travel.

Air travel is down dramatically in the last few weeks, with the TSA recording fewer than 200,000 travelers passing through its checkpoints per day this week, compared to more than 2 million at the same time last year. On Tuesday, it reported screening just 146,348 travelers, a ten-year low.

Rail travel is also severely limited, with Amtrak reporting record cancelations and low bookings, which has forced reductions on many of its routes. Trump said he was considering “similar” restrictions on railroads between virus hot spots.

“We have trains going back and forth, people don't think of trains but we do a lot of transportation business,” Trump said at the briefing.

“When you start closing up entire transportation systems and opening them up, that's a very tough thing to do,” he said.