U.S. stock futures and the dollar were little changed on Sunday after Republican presidential candidate Donald Trump was safe following what the FBI said appeared to be an assassination attempt outside Trump's golf course in West Palm Beach, Florida.

Secret Service agents engaged a gunman in some bushes near the property line of the golf course and fired at least four rounds of ammunition, law enforcement officials said during an afternoon press conference.

S&P 500 e-minis were down 0.04%. The Dollar Index , which measures the U.S. currency's strength against six major peers, was down 0.03% to 101.07.

Bitcoin was 0.7% lower on the day at $59,445. Trump has positioned himself as a pro-cryptocurrency candidate.

While there was little market reaction to the news, analysts said the incident had the potential to spur volatility.

"Foreign exchange rates could experience turbulence in the coming hours as news of a second assassination attempt lands amid thin trading volumes," said Karl Schamotta, chief market strategist at payments company Corpay in Toronto.

Asset classes and sectors seen benefiting from a second Trump term received a boost earlier this year after Trump survived in an assassination attempt in Pennsylvania on July 13.

The so-called "Trump trade," however, came under pressure last week after a closely watched debate between Trump and Vice President Kamala Harris left betting markets pegging a stronger likelihood of a Harris win in November.

"Perhaps we may see some look to get back into the 'Trump Trade' if this sees Trump receive a boost in the polls like we saw after the earlier assassination attempt - boosting both equities, and the dollar," said Michael Brown, senior research strategist at online broker Pepperstone, in London.

"That said, with the FOMC looming large on Wednesday, conviction among market participants will likely be lacking until we hear from Powell & Co," he said.

Betting markets logged little reaction to the incident on Sunday, with Harris' odds in PredictIt's 2024 presidential general election market at 56 cents, while Trump's odds were at 47 cents.

The Federal Reserve is in focus as uncertainty swirls over how much the U.S. central bank will cut interest rates at its -Sept. 17-18 monetary policy meeting and the pace at which it will reduce borrowing costs in coming months.

"The dollar could yet climb on a modest recovery in the 'Trump trade,' but any effect should be relatively modest in scale," Corpay's Schamotta said.