WEST PALM BEACH, Fla. — President Trump defended a decision that would bar foreign nationals who had recently visited China from entering the United States as his administration continued to assess the growing threat of a coronavirus outbreak.

Sitting with the Fox News personality Sean Hannity, Mr. Trump used a roughly nine-minute interview taped on Saturday evening at Mar-a-Lago, his private club in Florida, and broadcast on Sunday as an opportunity to condense his usual rally-speak into Super Bowl pregame chatter. The topics included the virus, his impeachment and quick-paced insults of his potential 2020 rivals.

“We pretty much shut it down coming in from China,” Mr. Trump said of the coronavirus. “But we can’t have thousands of people coming in who may have this problem, the coronavirus. We’re going to see what happens, but we did shut it down, yes.”

He said his administration was offering the Chinese “tremendous help” to contain the spread of the virus. On Sunday afternoon, the administration put into effect a rule that would also essentially quarantine American travelers who had visited China within the past two weeks, diverting them to seven airports “to implement enhanced screening procedures,” according to guidelines issued Sunday by the Department of Homeland Security.