GENEVA (AP) — World Health Organization chief Tedros Adhanom Ghebreyesus said he will self-quarantine after being identified as a contact of a person who tested positive for COVID-19. A top WHO official focusing on the pandemic said Monday there has been no transmission at the agency's Geneva headquarters.

The 55-year-old Tedros tweeted late Sunday that he is “well and without symptoms,” but will self-quarantine in “coming days, in line with WHO protocols, and work from home.” His agency followed that up on Monday with its own tweet apparently aimed to dispel misinformation about his decision, writing: “Contrary to some incorrect reports, @DrTedros hasn’t tested positive for #COVID19.”

But the agency suggested later that Tedros hadn't been tested at all — and wasn't required to undergo a test under its current protocols. Tedros and WHO didn't identify the contact who had tested positive.

Speaking at a regular WHO briefing, Maria Van Kerkhove, WHO’s technical lead for the COVID-19 pandemic, said there had been no transmission of the virus at the agency's main site in Geneva — a city like others across Europe that has faced a spike in cases in recent days, prompting new lockdown measures by local authorities.

“We haven’t had any transmission take place on the premises, and we have no clusters on the premises,” Van Kerkhove said. “But it is something that we’re monitoring every day.”

Dr. Mike Ryan, the WHO's emergencies chief, said its “current protocols” don't require Tedros to be tested for the virus, and said “his testing will depend on the arrival of symptoms or otherwise, and he may be tested in the days to come."

WHO has tallied “a number of cases” since the outbreak swept the globe earlier this year, Ryan said, adding that “most cases have been acquired at community level, very few within the building here."

Asked about the contradiction about whether any transmission had occurred on-site, WHO spokeswoman Margaret Harris said the public position from the agency was that there has been none at headquarters.

Tedros’ self-quarantine highlights the risks and challenges that many businesses and organizations face in keeping COVID-19 at bay, and who a U.N. agency office teeming with medical experts, renowned scientists and specialists on viruses is no exception.

Ryan noted that staffers who enter the building undergo temperature checks upon arrival, are asked to self-declare about their health status every day, and can benefit from “an immediate response mechanism” if he or she becomes ill at home or the office.

“This is not a zero-risk situation. We’ve said it again and again,” he said. “There is ... no environment right now in the world without risk.”

The WHO director-general and his team have been at the forefront of the global response to the coronavirus pandemic, which has infected at least 46.5 million people and led to more than 1.2 million deaths, according to a count of confirmed cases by Johns Hopkins University.

Cases have been increasing in Geneva, where tighter restrictions were announced Sunday aimed to curb the spread of the virus. More than 1,000 new cases have been recorded each day recently in an area of about 500,000 people, local officials said Sunday.

In what have become twice-weekly WHO news conferences, Tedros and other leaders of the health agency have generally opted not to wear protective masks, insisting that they have taken other precautions such as physical distancing and ensuring good air circulation in the vast conference room where the briefings take place.

Officials at WHO Europe in Copenhagen, however, regularly wear masks during their weekly news conferences in an effort to send a signal to viewers about precautions to take.