The US Secret Service said on Saturday night an incident at a campaign event for Republican presidential candidate Donald Trump in Reno, Nevada, began when someone shouted "gun" but no weapon was found.
"Immediately in front of the stage, an unidentified individual shouted 'gun.' Secret Service agents and Reno Police Officers immediately apprehended the subject. Upon a thorough search of the subject and the surrounding area, no weapon was found," the Secret Service said in a statement.
"A thorough investigation is ongoing at this time by the US Secret Service and the Reno Police Department," it said.