UNITED NATIONS (Reuters) - A female diplomat from the Philippines mission to the United Nations tested positive for coronavirus on Thursday, according to a note sent to U.N. missions, making the woman the first known case at the world body’s New York headquarters.

“As of today, the Philippine Mission is in lockdown, and all personnel are instructed to self-quarantine and to seek medical attention should they develop the symptoms. We are assuming that all of us have been infected,” wrote Philippines acting U.N. Ambassador Kira Azucena in a message seen by Reuters.

According to the online U.N. directory of diplomatic staff, there are about 12 diplomats at the Filipino mission, which is on 5th Avenue in Midtown Manhattan.

The Philippines Foreign Secretary Teodoro Locsin posted on Twitter that the diplomat was young, spritely and “doing well,” adding that she had recently returned from Florida.

The sick diplomat represented the Philippines in the U.N. General Assembly’s legal affairs committee. Azucena said the diplomat was last at U.N. headquarters on Monday for about half an hour when she was asymptomatic.

She came down with flu-like symptoms on Tuesday and visited her doctor. “She got the call today that she tested positive for COVID-19,” Azucena wrote on Thursday.

U.N. spokesman Stephane Dujarric said the Filipino diplomat met with two other diplomats and visited only one U.N. meeting room, which had been cleaned three times since Monday. He said the U.N. medical services was contacting those diplomats.

Several U.N. meetings planned for Friday had been canceled in the wake of the diagnosis, diplomats said.

The 193-member world body began implementing coronavirus prevention measures at its Manhattan headquarters this week, including closing off access to the public, more regular cleaning and cancelling some meetings. Half the several thousand U.N. staff who normally work in the building will work from home by next week.

The World Health Organization has described the coronavirus outbreak as a pandemic. The virus, which has been deadly for some people, broke out in China’s Wuhan city late last year and has so far infected some 125,000 people from 118 countries and territories. According to a Reuters tally it has killed 4,700.