UNITED NATIONS - 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 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 sick diplomat represented the Philippines in the U.N. General Assembly's legal affairs committees. 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.

Philippine Foreign Affairs Secretary Teddyboy Locsin confirmed the report, saying the diplomat from the Philippines mission who tested positive for the coronavirus is "doing well."

"The infected is doing well; she's young, spritely, smart and taking some doctor prescribed meds. Thank you. I just talked to Kira,” Locsin said in a tweet as he replied to a tweet made by Michelle Nichols, UN Bureau chief of Reuters.

In a separate tweet, Locsin added: "It was after celebrating her birthday with friends during a light rain and she'd just come from Florida.”

The United Nations did not immediately respond to a request for comment on the case.

The 193-member world body began implementing coronavirus prevention measures at its Manhattan headquarters this week.

A two-week conference on women's rights was cut to one day, several other planned large conferences canceled, most smaller meetings cut, U.N. missions asked to limit the number of diplomats they send to meetings, and at least half the several thousand U.N. staff who normally work in the building will be working 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. With a report by Willard Cheng, ABS-CBN News