A Pakistani man with ties to Iran has been charged over an alleged plot to assassinate US politicians and officials.
FBI director Christopher Wray called the scheme a "dangerous murder-for-hire plot... straight out of the Iranian playbook".
Asif Merchant, 46, is accused of attempting to hire a hitman in New York to kill prominent American officials. CBS, the BBC's news partner, quoted sources as saying Donald Trump was among the targets.
Security for the Republican presidential nominee was increased in June after authorities learned of an Iranian plot to kill him.
"A foreign-directed plot to kill a public official, or any US citizen, is a threat to our national security and will be met with the full might and resources of the FBI," Mr Wray said on Tuesday.
While the indictment does not mention Trump by name, sources cited by CBS said that the former president was one of the intended targets.
The plot is unrelated to the assassination attempt on the former president at a rally in Butler, Pennsylvania, on 13 July, by 20-year-old Thomas Matthew Crooks, who was shot and killed by a Secret Service sniper on site.
Trump and officials including his former secretary of state, Mike Pompeo, have faced threats from Tehran since ordering the drone strike assassination of Qassim Soleimani, the commander of Iran's Quds force, in Iraq in 2020.
Mr Merchant was arrested in July and is being held in New York.
According to the justice department's indictment, Mr Merchant arrived in the US from Pakistan in April after having spent time in Iran.
After arriving, he allegedly contacted a person whom he believed could help with the assassination plot. That unnamed contact later reported Mr Merchant to the police.
Mr Merchant allegedly made a "finger gun" motion with his hand when talking about what he wanted to do.
The indictment said the job would not be a "one-time opportunity" and that contacts services would be needed on an ongoing basis.
Mr Merchant allegedly told the contact he planned to leave the US before targets were killed, and that he would stay in contact using code words.
The suspect asked the contact to arrange a meeting with would-be assassins, the indictment says. The contact then connected him in June to undercover FBI agents posing as hitmen.
Mr Merchant allegedly told the agents they were to steal documents from the home of a target, arrange protests at political rallies, and kill a "political person".