A Washington staffer for Sen. Maria Cantwell (D-Wash.) has tested positive for the novel coronavirus, in what’s believed to be the first confirmed case of covid-19 on Capitol Hill, her office announced Wednesday night.

“The individual has been in isolation since starting to have symptoms,” the office said in a public notice. “On the advice of the Attending Physician, the senator has closed her Washington, D.C. office this week for deep cleaning and staff will be teleworking.”

According to the notice, the infected Senate staffer, who has not been publicly identified, “had no known contact with the senator or other members of Congress.”

“The senator is requesting that testing be done on any other staffers who have been in contact with the individual and show symptoms,” her office said.

A spokesperson for Cantwell did not immediately return a request for comment early Thursday.

The first diagnosed case of covid-19 on Capitol Hill was announced on a day packed with coronavirus news: The World Health Organization officially declared the virus a global pandemic and President Trump announced he was restricting travel to the United States from Europe (but not the United Kingdom) for 30 days, beginning Friday at midnight.

The notice comes as Public Health - Seattle & King County on Wednesday reported four new deaths, all of whom were residents at senior care facilities. The death toll in the state is approaching 30 as of early Thursday. Washington Gov. Jay Inslee (D) also announced Wednesday a ban on gatherings of more than 250 people in King, Snohomish and Pierce counties.

Hours earlier in the District of Columbia, Mayor Muriel E. Bowser (D) declared a state of emergency after six more cases of coronavirus were confirmed. Her declaration included a recommendation that gatherings of 1,000 or more people be suspended until March 31.

On Capitol Hill, leaders in the House and Senate agreed on Wednesday to limit the public’s access to Congress, canceling tours through the end of the month.

No members of Congress have been diagnosed with covid-19, but some have taken precautionary measures this week. At least seven members of Congress, including Rep. Mark Meadows (R-N.C.), Trump’s incoming chief of staff, have either self-quarantined or isolated themselves after coming in contact with someone who has been infected with coronavirus.

Earlier this week, Cantwell pleaded for increased testing for coronavirus in Washington state and the rest of the nation.

“We’re not where we want to be on testing in my state or in the nation,” she told MSNBC’s Chris Hayes. She later added, “Test more. Get them done faster. Release the information, so that we can have the mitigation strategies that can help all of us.”