White House Republican candidate Donald Trump was rushed off stage by security officers Saturday after a false gun scare during a campaign appearance.
The US Secret Service, which provides security for presidential candidates, later said someone in the crowd had shouted "gun" but that no weapon was found.
Trump swiftly resumed his speech in Reno, Nevada after a suspect, who was wrestled to the floor during the incident, was briefly detained then released.
The 70-year-old real estate tycoon reappeared to cheers just minutes after being led away by Secret Service agents who shielded his body with their own.
"Nobody said it was going to be easy for us, but we will never be stopped, never ever be stopped," he declared.
"I want to thank the Secret Service. These guys are fantastic. They don't get enough credit. They don't get enough credit. They are amazing people."
Just before the fracas, Trump was seen shielding his eyes from the lights in order to peer into the crowd as a struggle broke out.
Trump "was removed from the stage" by agents in his protective detail "after a commotion occurred in the crowd," the Secret Service said.
"Immediately in front of the stage, an unidentified individual shouted 'gun'. Secret Service agents and Reno Police Officers immediately apprehended the subject."
However no weapon was found following "a thorough search" of the subject and the surrounding area, the statement said.
Television footage showed a suspect pinned to the ground by officers and searched, before he was led away by local law enforcement.
The candidate appeared unrattled and spoke with his usual self-confidence, finishing his planned remarks and accepting applause before returning to his plane safely.
"I'm actually a Republican ... but I just don't support Donald Trump," the protester, who identified himself as Austyn Crites from Reno, told reporters after he was released.
Crites, 33, said that he agreed with Trump on many issues, but added: "I believe that he's very dangerous for the country."
Crites told NBC News 4 that he came armed "with just one sign that said 'Republicans against Trump.'"
The protester told The Guardian that he was knocked to the ground, punched, kicked and choked by Trump supporters when he attempted to silently hold up the sign.
On social media, Trump supporters pilloried him as a Hillary Clinton mole, pointing to what they said was his deleted pro-Hillary Facebook page.
Crites told The Guardian that he believes the Democratic candidate is the only person who can stop Trump, and said that he briefly canvassed for her campaign.
Trump, in a campaign statement, thanked the Secret Service and local and state law enforcement "for their fast and professional response."
Trump's events during this long campaign season have often been disrupted by protesters, but this is only the second time that the candidate was bundled off stage by security.