WASHINGTON -- The US State Department on Saturday raised its travel advisory for Daegu to the highest level, urging Americans not to travel to the South Korean city most affected by the coronavirus.

The advisory was raised to Level 4, which means "do not travel," due to the level of community transmission of the virus and imposition of local quarantine procedures, the department said on its website. The rest of South Korea remained under Level 3, which means "reconsider travel."

The notice was posted shortly after US Vice President Mike Pence, who is overseeing the US response to the coronavirus, announced the restriction at a White House press briefing.

"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," the vice president said as President Donald Trump looked on. He did not identify the affected regions.

Pence said that the president had authorized the State Department to increase the travel advisory.

"The president's also directed the State Department to work with our allies in Italy and in South Korea to coordinate a screening, a medical screening, in their countries of any individuals that are coming in to the United States of America," he added. "We look forward to working with them in a collaborative and a cooperative way."

Last Saturday, the State Department raised the travel advisory for South Korea to Level 2, urging "increased caution," and then on Wednesday to Level 3.

South Korea has reported 3,150 cases of COVID-19, with 17 deaths. Daegu, the epicenter of the outbreak in the country, has confirmed more than 2,200 cases. Neighboring North Gyeongsang Province has seen 488 cases. Together, the two make up for 86 percent of all infections in the country.

The numbers are expected to increase further as the government continues tests on followers of a religious sect at the center of the massive outbreak.

The White House announcement came shortly after the US reported its first death of a coronavirus patient, in the state of Washington.

Earlier Saturday, US Forces Korea confirmed its fourth coronavirus infection, in the spouse of a USFK soldier stationed in the southeastern county of Chilgok.

"We care very much for the troops," Trump said when asked about the situation with the 28,500-strong USFK. "We're in constant touch with the troops. We've been speaking to the general ... And that's all working out fine, and we're in touch with the authorities in South Korea, too." (Yonhap)