Los Angeles Mayor Eric Garcetti tested positive for COVID-19 Wednesday while attending the U.N. climate conference in Glasgow, Scotland, an event that has drawn world leaders and tens of thousands of other people from around the world.

His office announced a positive test result in a tweet, adding only: “He is feeling good and isolating in his hotel room. He is fully vaccinated.”

The climate summit is taking place at a time of very high coronavirus rates in the United Kingdom. The conference’s United Nations organizers laid down rigid rules to guard against infection, including requiring each attendee to wear a mask and show daily proof of a negative result to enter the venue each morning.

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Garcetti arrived Monday on a train with other mayors from around the world, including from London, Paris, Dhaka, Bangladesh, and Freetown, Sierra Leone. Garcetti has been among countless political and science leaders giving speeches, appearing on panels, posing for group photos and conferring with others at the climate talks.

Like many other participants, Garcetti varied between wearing a mask and not, photos from the summit show.

In an interview from his hotel room with KNX radio in Los Angeles, Garcetti said he was experiencing a mild scratchy throat and slightly runny nose but otherwise was “feeling good.”

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He said he was hoping the test was incorrect – a so-called false positive — but planned to keep up a regular work schedule if required to continue a quarantine at his hotel.

President Joe Biden nominated Garcetti as ambassador to India and he is awaiting confirmation in the Senate.

Garcetti’s 9-year-old daughter contracted coronavirus last December, when Los Angeles was experiencing its worst surge. Garcetti and his wife never got it but were forced to quarantine with their daughter.

Summit spokesman Alexander Saier declined comment, saying officials were not speaking on individual cases.

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About 25,000 people picked up badges at the summit, Laura Lopez, conference affairs director for the summit, said Wednesday before news of Garcetti’s positive test. Of them, 97% have been vaccinated.

Lopez said there had been roughly eight COVID cases, including one U.N. employee.

On Monday, the day world leaders spoke at the summit, about 1,000 people came to the front turnstiles without doing their lateral flow tests, she said. They were taken to a separate site and tested before being allowed in.

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Organizers briefly closed the entry points that same day when the number of people inside hit 10,000, another precaution against infection.

Britain’s government recorded 33,865 infections Tuesday and 293 deaths, the highest daily death figure since February. While the number of cases have been coming down from a peak of around 46,000 a day in October, the country’s case rates are still much higher than in most of Europe.

So-called breakthrough infections among fully vaccinated people are rare, although vaccinated people can spread the virus to others.