WASHINGTON -- Donald Trump was rushed off a stage here Saturday by Secret Service agents during a campaign speech after an incident in the crowd near the front of the stage.
A Secret Service spokesperson said in a statement that an "unidentified individual" shouted "gun" in the audience, though no weapon was found after a "thorough search."
The suspect was immediately taken into custody and led out by a throng of police officers, Secret Service agents and SWAT officers armed with assault rifles to a side room.
The Secret Service did not immediately provide further details and said an investigation was ongoing.
Trump was unharmed and returned to the stage minutes later to finish his speech.
Trump was in the middle of his stump speech when the commotion occurred. He was looking into the crowd, his hand over his eyes to block the glare from the stage lights, when Secret Service agents grabbed him and escorted him off the stage. Trump ducked his head as he left the stage.
The crowd surged backward, some supporters with frightened looks on their faces, as the Secret Service and police tactical units rushed in to detain a man.
Several attendees told CNN they initially heard a person yell there was someone with a gun.
"We were all very interested in what Mr. Trump had to say and a guy in a red shirt rushed right next to me, screaming there is a guy with a gun," Simon Cohen told CNN.
But asked if he saw a gun, he said, "No, I did not."
A second person, Milton Zerman, said he "was watching Trump speak and I heard someone scream, 'This guy has a gun,' so I looked toward the guy he was talking about. It didn't look to me that he had a gun -- or at least I didn't see a gun -- but people were screaming that he did have a gun and immediately after that Trump was taken off stage.
"Everyone starts dispersing, I hear people saying, 'Let's get out of here, it's not going to be good,' but I just took that opportunity to get closer to the front because it seemed like the police officers had it under control."
A message left with the Trump campaign was not returned. A spokesman for the Reno police department directed media inquiries to the Secret Service.
The Republican nominee returned to the stage several minutes later.
"Nobody said it was going to be easy for us, but we will never be stopped. We will never be stopped. I want to thank the Secret Service. These guys are fantastic."
He then returned to his regular stump speech. Trump is scheduled to speak later Saturday night at a rally in Denver.
He later issued a statement about the incident.
"I would like to thank the United States Secret Service and the law enforcement resources in Reno and the state of Nevada for their fast and professional response," he said. "I also want to thank the many thousands of people present for their unwavering and unbelievable support. Nothing will stop us -- we will make America great again!"
Less than an hour after the incident -- and before it was clear what happened -- Trump's campaign sought to highlight the moment to suggest he was tougher than his Democratic rival, Hillary Clinton, who had to cut short a Florida rally due to heavy rain.
Dan Scavino Jr., Trump's social media director, and Donald Trump Jr., the nominee's oldest son, retweeted Jack Posobiec, a supporter who wrote: "Hillary (Clinton) ran away from rain today. Trump is back on stage minutes after assassination attempt."
But the Secret Service statement made clear no weapon had been found.
Secret Service agents rushed to shield Trump onstage in March after a man tried to rush the stage during a rally in Dayton, Ohio, but the GOP nominee wasn't escorted off stage.
And a man was arrested at a rally in Las Vegas in June after he tried to grab a police officer's gun, which he said he planned to use to shoot Trump.