Two more Trump election waiters in Oklahoma were positive for nCoV, bringing the number of cases in this team to eight.

"After another test, two more team members serving the Tulsa campaign were positive for nCoV. These employees attended the campaign, but wore masks during the entire event."

Earlier, Trump's campaign announced that six employees serving a rally in Tulsa, Oklahoma were infected with nCoV.

Murtaugh said that according to the safety process, campaign employees were tested for Covid-19 before the events, adding that 6 cases of nCoV were detected on June 20 after hundreds of tests and they were immediately quarantined.

People attending Trump's speech in Tulsa are not required to wear masks or adhere to community isolation, although US health officials have issued recommendations.

Earlier, the registration website for the Tulsa campaign required voters to pledge "bear all risks related to Covid-19".

The Tulsa event opened the door for Trump's campaign for re-election to the White House since Covid-19 attacked, prompting all direct election campaigns to halt.

The Tulsa Fire Department said fewer than 6,200 people attended the rally, lower than what Trump's campaign expected.

More than 210 countries and territories have appeared Covid-19, after the outbreak broke out in December 2019 in Wuhan, China, leaving nearly 9.2 million infected, more than 474,000 dead.