The US justice department is bringing criminal charges over an Iranian plot to kill the president-elect, Donald Trump, that was thwarted by the FBI, the government said.

The federal government has unsealed criminal charges in what the justice department said was a murder-for-hire plan to take out Trump before this week’s presidential election, which he won decisively over his Democratic rival, Kamala Harris.

A criminal complaint filed in federal court in Manhattan alleges that an unnamed official in Iran’s paramilitary Revolutionary Guards instructed a contact this past September to put together a plan to surveil and ultimately kill Trump.

Investigators learned of the plot while interviewing Farhad Shakeri, an Afghan national identified by officials as an Iranian government asset who was deported from the US after being imprisoned on robbery charges.

He told investigators that a Revolutionary Guard contact in Iran instructed him in September to devise a plan within seven days to surveil and ultimately assassinate Trump, according to the criminal complaint.

Two other men who the authorities say were recruited to participate in other assassinations, including a prominent Iranian American journalist, were also arrested on Friday. Shakeri remains in Iran.

“There are few actors in the world that pose as grave a threat to the national security of the United States as does Iran,” the US attorney general, Merrick Garland, said in a statement on Friday.

In September, US intelligence officials told Trump about a suspected Iranian plot to kill him, his campaign said at the time.

The briefing, from the Office of the Director of National Intelligence (ODNI), was believed to have focused on a scheme unrelated to two failed domestic assassination attempts against the Republican then nominee for president, and came amid reports suggesting that Iran was conducting an ongoing hack against Trump’s campaign.

The campaign at the time said the briefing concerned “real and specific threats from Iran to assassinate [Trump] in an effort to destabilize and sow chaos in the United States”.

The plot reflects what federal officials have described as ongoing efforts by Iran to target US government officials, including Trump, on US soil. Last summer, the justice department charged a Pakistani man with ties to Iran in a murder-for-hire plot.

The Associated Press contributed reporting