Donald Trump has been accused of calling for the assassination of his presidential rival, Hillary Clinton.
Talking to supporters in North Carolina, the Republican candidate said he needed to win the presidency to stop the Democratic Party winning control of the Supreme Court and implementing tougher gun control laws.
"Hillary wants to abolish, essentially, the Second Amendment," Trump told the crowd in Wilmington.
"By the way, and if she gets the pick, if she gets the pick of her judges, nothing you can do, folks. Although the Second Amendment people, maybe there is, I dunno."
The Second Amendment to the US Constitution is the one which Republicans believe gives ordinary Americans the right to own and use guns, including military-style rifles used in mass shootings in Florida and Sandy Hook.
Ms Clinton's campaign manager Robby Mook was quick to condemn Trump's comments.
"This is simple - what Trump is saying is dangerous. A person seeking to be President of the United States should not suggest violence in any way."
Trump's team denied he was calling for anyone to be shot, blaming the "dishonest media" for twisting his words.
"It's called the power of unification," Trump senior communications advisor Jason Miller said in a statement. "Second Amendment people have amazing spirit and are tremendously unified, which gives them great political power. And this year, they will be voting in record numbers, and it won't be for Hillary Clinton, it will be for Donald Trump."
Gun control advocate and Democrat Senator Chris Murphy said Trump's comment was not a "political misstep", and increases the likelihood "unstable people" would literally try and kill Ms Clinton or her nominees to the Supreme Court.
"It's an assassination threat, seriously upping the possibility of a national tragedy and crisis," he tweeted.
Former director of the Central Intelligence Agency Michael Hayden told reporters if "someone said that outside hall, they'd be in a police wagon being questioned by Secret Service".
Trump, as a candidate for President, is already being watched by the Secret Service. It says it is "aware of the comment", but it's not clear yet if Trump is under formal investigation.
Even some in the Wilmington crowd listening to Trump's comments seemed shocked by the comment, while others laughed.
The National Rifle Association (NRA), which has previously endorsed Trump tweeted if Ms Clinton "gets to pick her [anti-Second Amendment Supreme Court] judges, there's nothing we can do".
The NRA didn't comment on Trump's "maybe there is" comment, but urged supporters to back Trump at the election.
Threatening to harm a presidential candidate is a felony, punishable by up to five years in prison.
Trump trails Ms Clinton in the polls, some showing him behind by double-digits.