A health personnel checks the body temperature of a pilgrim returning from Iran via the Pakistan-Iran border town of Taftan on February 29, 2020.

The president, meanwhile, said he will meet with some of the globe's largest pharmaceutical companies on Monday on efforts to develop a vaccine for the novel illness. He and Health and Human Services Secretary Alex Azar added that the administration's early action to clamp down on travel has helped keep the virus's risk to everyday Americans low.

"We are going to increase, to the highest level advisory — which is Level 4 — advising Americans: Do not travel to specific regions in Italy and South Korea," he added. "We are urging Americans to not travel to the areas in Italy and the areas in South Korea that are most affected by the coronavirus."

"First, the president authorized action today to add additional travel restrictions on Iran. … Iran is already under a travel ban, but we're are expanding existing travel restrictions to include any foreign national who has visited Iran within the last 14 days," Pence said.

President Donald Trump authorized the expansion of travel restrictions against Iran and the new recommendation that Americans refrain from visiting regions of Italy and South Korea impacted by the coronavirus.

U.S. President Donald Trump speaks as Vice President Mike Pence looks on during a news conference at the James Brady Press Briefing Room at the White House February 29, 2020 in Washington, DC.

"We moved very early. That was one of the decisions we made that really turned out to be a lifesaver, in a sense. A big lifesaver," Trump said. "I want to say that China seems to be making tremendous progress. Their numbers are way down ... If you read, Tim Cook of Apple said that they're now in full operation again in China."

The weekend presser comes shortly after Washington state confirmed the first death in the U.S. from the virus, and less than 24 hours after Trump categorized the criticism of his administration's response to the disease as a new "hoax" cooked up by Democrats in an effort to attack him.

The president also sought to clarify his use of the word "hoax" at Friday's rally.

"The 'hoax' was used with respect to Democrats and what they were saying," Trump said. "It was a 'hoax,' what they were saying."

The news conference also follows the worst week for U.S. markets since the financial crisis, with the Dow Jones Industrial Average and the S&P 500 down 12.36% and 11.49% since the opening bell on Monday. Both major stock indexes fell into what's known on Wall Street as a correction, a slide of 10% or more from a recent 52-week high.

Corrections often signal that investors have realized equities are overpriced, that there's a new and previously unknown threat to the market, or both. Investors say that the rapid spread of coronavirus, formally labeled COVID-19, has scared many that the illness could eventually weigh on U.S. economic growth, manufacturing and exports.

The disease, which originated in Wuhan, China, has killed more than 2,800 people worldwide and infected more than 80,000.

In the U.S., Oregon reported on Friday its first case of the virus. Officials said the person has no history of travel to a country where the virus is known to be circulating, and is not believed to have had close contact with other confirmed cases.

That followed an announcement by the Santa Clara Public Health Department, which announced on Friday a third case of coronavirus in the county. The announcement brought the total number of confirmed coronavirus cases in California to 10.

There are at least 64 confirmed cases in the U.S., but the three new cases on Friday and one earlier in the week were the first in the country in which the cause of the infection is unknown.

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