Four people have tested positive for COVID-19 after attending the Republican National Convention in Charlotte, North Carolina, Mecklenburg County officials told Friday.  

The city, which hosted the first night of the convention for President Donald Trump‘s reelection campaign, announced that its officials conducted COVID-19 tests for almost 800 attendees and workers. 

“[COVID-19 positive] individuals were immediately issued isolation instructions and any known close contacts were notified and issued quarantine instructions by Mecklenburg County Public Health (MCPH),” officials said. 

In response to the report, the RNC claimed that it had well-thought-out protocols, including a contact tracing and requiring its attendees to wear masks and social distance. Attendees were also told to have their temperature measured and complete a wellness questionnaire.

“The RNC had diligent safety protocols in place, including testing all attendees before arriving in Charlotte, and again upon arrival,” RNC Communications Director Michael Ahrens told CBS News.

“Out of roughly 1,000 tests administered, two RNC attendees, despite having negative tests prior to travel, and two Charlotte locals who planned to serve as event support staff tested positive upon arrival. All were sent home.”

The RNC events were heavily criticized by health experts, including Dr. Ashish Jha, the Director of the Harvard Global Health Institute.

“This is deeply irresponsible. It goes against all that we know about keeping people safe. We should expect better from our national leaders,” Jha said, according to the reports from CNN’s Jake Tapper