Democrats have attacked US presidential nominee DonaldTrump after he ignited a fresh political firestorm by declaring gun rights supporters might still find a way to stop Hillary Clinton, even if she should defeat him and then name anti-gun Supreme Court justices.

Democratic Party members accused the billionaire Republican of openly encouraging violence against his election opponent.

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Mr Trump has been working this week to move past distracting campaign disputes, but once again he put himself at the centre of a blazing controversy.

First, he falsely claimed that Mrs Clinton wanted to "essentially abolish the Second Amendment". She has said repeatedly that she supports the Second Amendment right to own guns, but backs some stricter controls.

Mr Trump then noted the power Mrs Clinton would have to nominate justices to America's top court.

"By the way, if she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people - maybe there is, I don't know," Mr Trump told supporters at a rally in Wilmington, North Carolina. "But I'll tell you what. That will be a horrible day."

The reaction from Democrats was immediate. Clinton campaign manager Robby Mook said: "This is simple - what Trump is saying is dangerous. A person seeking to be the president of the United States should not suggest violence in any way."

Mr Trump's reaction as the uproar grew was: "Give me a break."

Interviewed by Fox News' Sean Hannity, he said everyone in his audience knew he was referring to the power of voters and "there can be no other interpretation".

Mr Trump's campaign sought to quell the controversy with a statement that blamed the "dishonest media" for misinterpretation. And Mr Trump's running mate, Indiana governor Mike Pence, said his boss was talking about the election choice for pro-gun voters, not encouraging violence.

But Mr Trump's foes were unconvinced and unforgiving.

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Tim Kaine, the Democratic vice presidential nominee, said: "I think it was just revealing and I don't find the attempt to roll it back persuasive at all."

Priorities USA, a super PAC - expenditure-only committee - supporting Mrs Clinton, said MrTrump had "suggested that someone shoot Hillary Clinton".

Across the country, Democratic House of Representatives and Senate candidates piled in, working to tie Mr Trump's comments to their Republican opponents.

The Brady Campaign to Prevent Gun Violence, which has endorsed Mrs Clinton, said MrTrump was encouraging gun violence "based on conspiracy theory about Hillary Clinton".

Senator Elizabeth Warren, a Massachusetts Democrat, tweeted: "@realDonaldTrump makes death threats because he's a pathetic coward who can't handle the fact that he's losing to a girl."

The National Rifle Association, the gun lobby that has endorsed Mr Trump, came to his defence, writing on Twitter that "there's nothing we can do" if Mrs Clinton is elected, urging voters to defeat her in November.

The controversy immediately overwhelmed Mr Trump's intended campaign-trail focus: the economic plan he unveiled just a day earlier and was promoting during a series of rallies in the most competitive general election states.

It also reinforced the concern, voiced by many worried Republicans, that he cannot stay disciplined and avoid inflammatory remarks that imperil not only his White House prospects but the re-election chances of many party politicians.

House of Representatives speaker Paul Ryan, who was celebrating a primary victory in Wisconsin, said: "It sounds like just a joke gone bad. I hope they clear this up very quickly. You never joke about something like that."

At another rally later in Fayetteville, North Carolina, Mr Trump was careful with his words. He repeated his argument that Mrs Clinton posed a threat to gun rights, but avoided any talk about advocates taking matters into their own hands.

Former New York mayor Rudy Giuliani, introducing him, blamed the controversy on "disgusting" journalists.

Mrs Clinton's supporters are hoping the latest Trump trip-up will lead yet more of his fellow Republicans to defect. A day earlier, Maine senator Susan Collins became the latest to declare she would not vote for her party's nominee, explicitly pointing to his "constant stream of cruel comments".

The US Secret Service, responsible for both Mrs Clinton's and Mr Trump's protection, said it was aware of what Mr Trump had said, but declined to say whether it planned to investigate.

Contrary to Mr Trump's remarks, Mrs Clinton has made her support for gun rights a key piece of her stump speech in a bid to pre-empt attacks from Mr Trump and groups like the NRA.

But she supports reinstating a national assault weapons ban, expanding background checks and barring purchases by domestic abusers, among other steps.

"I'm not here to repeal the Second Amendment," she said in her Democratic National Convention speech. "I'm not here to take away your guns. I just don't want you to be shot by someone who shouldn't have a gun in the first place."

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She spent Tuesday in Florida calling for emergency public health action on the Zika virus while visiting the Miami area dealing with the first US outbreak.

At a local health clinic, she urged the US Congress to cut short its summer recess and immediately pass funding for a Zika response, blaming congressional Republicans for inaction.