Protesters take part in a demonstration in Tulsa, Oklahoma, the United States, on June 20, 2020. (Photo by Alan Chin/Xinhua)

Two more campaign staffers who attended President Donald Trump's rally in Tulsa, U.S. state Oklahoma, on Saturday have tested positive for the coronavirus, the campaign said Monday.

The new test results bring the number of Trump's campaign staffers for the Tulsa event who have tested positive for COVID-19 up to eight, including two secret service agents.

"After another round of testing for campaign staff in Tulsa, two additional members of the advance team tested positive for the coronavirus," said Trump campaign communications director Tim Murtaugh on Monday.

"These staff members attended the rally but were wearing masks during the entire event. Upon the positive tests, the campaign immediately activated established quarantine and contact tracing protocols," Murtaugh said.

The six earlier positive tests of advance campaign members occurred just before the event, and those people did not attend the rally as a result.

The number of people connected to the event who test positive is expected to rise, NBC News reported, citing campaign and law enforcement officials.

Oklahoma officials on Monday reported 478 new coronavirus cases, a record high for the state.

The Tulsa rally was Trump's first such campaign event since the coronavirus pandemic began in March. Trump's next campaign event is set to occur in Phoenix, Arizona, on Tuesday.