The U.S. ambassador to South Africa attended a dinner at President Trump’s Mar-a-Lago Club with Brazilian officials who later tested positive for the novel coronavirus. But she told her State Department employees that she did not consider herself at risk because the dinner was outside and she believed the virus could not withstand the Florida heat, according people familiar with the matter.

Ambassador Lana Marks made the claim during a “town hall” meeting for hundreds of staff members at U.S. diplomatic facilities in South Africa on Thursday, which was held following several days of concern among staff members who knew of her exposure. Details of the session were provided to The Washington Post afterward by people familiar with the ambassador’s remarks.

Employees voiced concerns during the meeting about Marks’s failure to self-quarantine or take other protective measures.

The people provided descriptions of the meeting and Marks’s actions on the condition of anonymity because they were not authorized to speak publicly. The State Department did not immediately respond to a request for comment.

State Department employees at Thursday’s meeting protested that they have been placed at risk, that Marks is not following the guidelines set by the Centers for Disease Control and Prevention and that she is incorrect that the virus could not have been transmitted at the outdoor dinner.

Marks, a fashion executive and Mar-a-Lago member, told staff at the meeting she would go into semi-seclusion but not cut out all meetings or contact with staff, these people said. She had previously told staff members who raised concerns that the incubation period has passed and that she does not believe she is at risk.

During the meeting, Marks said she was not in close contact with an infected person and that the temperature at Mar-a-Lago that night was above 26 degrees Celsius (about 79 Fahrenheit) and that the virus would not be transmissible at that temperature.

The virus is part of a family of viruses that generally spread quickest in cooler weather, but the properties and longevity of this new virus remain unclear.

She had previously told staff members at the embassy that she does not believe the positive test result for a close member of President Jair Bolsonaro’s staff, press secretary Fabio Wajngarten, people familiar with elements of that conversation said.

Brazil’s acting ambassador to the United States, who sat at Trump’s table at the dinner, has also tested positive, as has at least one other person who was at Mar-a-Lago that night.

Bolsonaro said his own test was negative. It is not clear whether Marks has been tested or will be.

At least two other U.S. officials, White House press secretary Stephanie Grisham and Sen. Lindsey O. Graham (R-S.C.), opted to enter self-quarantine after attending the same dinner.

Trump said he had been tested for the virus a week ago and that the test was negative. He has not self-isolated or self-quarantined, and his chief White House doctor said last week that neither Trump nor Vice President Pence need to do so.

Trump shook hands with the visiting Brazilian delegation and was photographed with Wajngarten, though he told reporters the interaction was fleeting.

“I take pictures, and it lasts for literally seconds. I don’t know the gentleman that we’re talking about. I have no idea who he is,” Trump said. “I take sometimes hundreds of pictures a day, and that night I was taking hundreds of pictures. So, I just don’t know.”

Public health and medical experts have urged people to stop shaking hands and touching their faces, limit large gatherings and self-isolate if they have come into contact with a confirmed case of the coronavirus because the disease spreads easily.

Shortly after the town hall meeting, Marks tweeted that she would enter self-quarantine, a shift from her stance before the employee session.

“[I]t is essential that everyone stays both safe and healthy — on a personal level, I am strongly advocating self-quarantine and social distancing for those who may, even by the remotest possibility, have been exposed,” she wrote.

“Returning to Pretoria, I had to take a fairly full flight. While nobody on the plane was diagnosed with #Covid19, and neither I nor my family are experiencing symptoms, in order to err on the side of extreme caution, we will self-quarantine for the prescribed 14 Days.”

That would apparently only mean self-quarantine until Saturday, 14 days after the March 7 dinner, but Marks’s plans were not immediately clear.

“I hope my personal actions serve as a good example to everyone who has recently travelled,” she wrote.

South Africa banned travel from the United States this past week, after Marks and her family had returned.

“At a time of pandemic, it is critical that professional medical advice be followed by every U.S. government employee, whether career or political appointee,” said Eric Rubin, president of the American Foreign Service Association.

“Our colleagues in the field are facing unprecedented threats and challenges. They need to know that their leaders have their welfare and well-being foremost in their minds, and that everything will be done to ensure the health and safety of our employees and their family members,” the union president said. “There is no room for individual decisions and no excuse for putting people at risk. Leaders need to be held to the highest possible standard at this time of danger.”

Several employees have said they were uncomfortable with Marks’s plans to hold flashy welcome festivities in Cape Town for the arrival of a U.S. Navy ship, the USS Carney, on March 15.

She insisted that the events would go forward, requiring extensive work by embassy employees who interacted with both the ambassador and many South Africans despite public health guidance against unnecessary gatherings, people familiar with the complaints said.

During the visit of the Arleigh Burke-class destroyer, Marks posed with the ship’s commanding officer, but many of the festivities were called off at the last minute.

Marks is a friend and neighbor of Trump’s in Palm Beach. The South African-born luxury handbag designer has no previous diplomatic experience but told senators at her 2019 confirmation hearing that her knowledge of the country and its languages qualifies her for the post.

Marks also said that her business experience would be a boon for the United States, adding that she started her business from the family kitchen table after she had settled in Miami.

Marks was named as the incoming ambassador in the summer of 2018, but her Senate confirmation hearing was held up for about a year. She was confirmed in September and took up her post in January.