A man who authorities say staked out Donald Trump for 12 hours on his golf course in Florida, and wrote of his desire to kill him, has been charged with attempting to assassinate the presidential candidate.
Ryan Wesley Routh, 58, had been initially charged with two federal firearms offences.
The upgraded charges reflect the Department of Justice's (DOJ) assessment that he methodically plotted to kill the Republican nominee, aiming a rifle through the shrubbery surrounding Trump's West Palm Beach golf course on an afternoon Trump was playing on it.
Mr Routh left behind a note in which he described his intention.
US Attorney-General Merrick Garland called the attempted assassination a "heinous act" on Tuesday, local time, and said his department will "spare no resource " on the case.
"The Justice Department will not tolerate violence that strikes at the heart of our democracy, and we will find and hold accountable those who perpetrate it. This must stop," the attorney-general said in a statement.
The DOJ said a federal grand jury in Miami returned the charge late Tuesday afternoon.
The attempted assassination charge carries a maximum sentence of life in prison.
The case has been assigned to US District Judge Aileen Cannon, who dismissed a criminal case in July accusing Trump of illegally keeping classified documents after leaving office.
Mr Routh has not yet entered a plea.
His lawyers unsuccessfully sought to have him released on bond.
Prosecutors have in recent days revealed evidence they said pointed toward a plan to kill Trump.
They alleged that months before the incident, Mr Routh dropped off a letter to an unidentified person alluding to "an assassination attempt on Donald Trump."
They said Mr Routh spent a month in South Florida and cell phone data showed him near the golf course and Trump's Florida residence at Mar-a-Lago.
He was found with a handwritten list of dates and venues where Trump spoke or was expected to appear, according to court filings.
Trump campaign warned of Iranian threats
Trump's campaign was warned by US intelligence of "real and specific" threats from Iran to assassinate him, according to his campaign.
"President Trump was briefed earlier today by the Office of the Director of National Intelligence regarding real and specific threats from Iran to assassinate him in an effort to destabilise and sow chaos in the United States," Trump campaign communications director Steven Cheung said on Tuesday.
Mr Cheung said "continued and coordinated attacks" by Iranian actors had increased in the past months.
The campaign did not elaborate on the claims, which come as Israel has carried out a bombing campaign in Lebanon against sites belonging to Lebanese group Hezbollah, backed by Tehran, killing nearly 600 people.
Iran rejected accusations that it is trying to kill Trump shortly after a gunman opened fire at a Trump rally in Pennsylvania, killing one person and wounding the presidential candidate.
Days after the July 13 assassination attempt, US media reported that authorities had received intelligence on an alleged Iranian plot against the Republican, prompting his protection to be boosted.
Iran rejected the "malicious" accusations.
The US has also accused Iran of a hack targeting Trump's campaign, alleging Tehran is seeking to influence the 2024 election.
Reuters/AFP/ABC