An Arizona sheriff who was set to join President Trump at the White House on Tuesday tested positive for the coronavirus before the meeting.

Pinal County Sheriff Mark Lamb said Wednesday he learned of his diagnosis through the White House visitor screening process.

“While still asymptomatic, I tested positive for the COVID-19,” he announced on Facebook.

Lamb, who will be self-quarantining for at least 14 days, said he believes he was infected during a campaign event he held last Saturday.

The Pinal County Public Health Department is “working to track all those I came into contact with” since Saturday, Lamb said.