President Donald Trump’s campaign said six staff members helping set up for his election rally in Tulsa, Oklahoma, have tested positive for coronavirus.
The campaign’s communications director Tim Murtaugh said “quarantine procedures” were immediately initiated and no staff member who tested positive would attend the event.
He said no-one who had immediate contact with those staff members would attend either.
Mr Murtaugh said campaign staff members are tested for Covid-19 as part of the campaign’s safety protocols.
Campaign officials said everyone who is attending the rally will be given temperature checks before they pass through security.
They will also be given masks to wear, if they want, and hand sanitiser at the 19,000-seat BOK Centre.
The rally is expected to be the biggest indoor event the country has seen since restrictions to prevent coronavirus from spreading began in March.
Tulsa has seen cases of Covid-19 spike in the past week, and the local health department director asked that the rally be postponed.
But Republican governor Kevin Stitt said it would be safe.
The Oklahoma Supreme Court on Friday denied a request that everyone attending the indoor rally wear a mask, and few in the crowd outside on Saturday were wearing them.