NEW YORK — Federal prosecutors in Manhattan said Friday that Iranian plotters had discussed a plan to assassinate Donald Trump before he was reelected as president this week.

One of the plotters said that he was assigned in September to carry out the plan by Iran’s Revolutionary Guard, prosecutors said in court papers.

An Iranian operative said he was told to put aside other efforts he was undertaking on behalf of the Revolutionary Guard and “focus on surveilling, and ultimately, assassinating” Trump, according to a criminal complaint filed in Manhattan federal court.

The operative told a Revolutionary Guard official that such a plan would cost a “huge” amount of money, the complaint said. In response, the official said, “We have already spent a lot of money,” adding that “money’s not an issue.”

The new allegation about a plan to kill Trump is the latest alarming development for U.S. security officials, who have been concerned since the summer that Iran appeared to be escalating plans for violence inside the U.S., including against the president-elect, who has been Tehran’s nemesis.

In his first term as president, Trump abandoned a nuclear deal that required Iran to limit its nuclear capacity. He levied 1,500 sanctions, including on oil sales and banking, debilitating the Iranian economy. And he ordered the assassination of a military leader, Gen. Qassem Soleimani, who had been designated as a terrorist.

This year, Iranian hackers breached Trump’s campaign and spread disinformation about the election. Officials said Friday that Tehran was willing to go further.

“The charges announced today expose Iran’s continued brazen attempts to target U.S. citizens, including President-elect Donald Trump, other government leaders and dissidents who criticize the regime in Tehran,” FBI Director Christopher Wray said.

Trump spokesman Steven Cheung said the president-elect was aware of the assassination plot and nothing will deter him “from returning to the White House and restoring peace around the world.”

The newly unsealed complaint also contains allegations that authorities had disrupted another plot to assassinate Masih Alinejad, a Brooklyn human-rights activist who has long criticized Iran’s repression of women.

The man prosecutors said was tasked with the plot to kill Trump and Alinejad was Farhad Shakeri, 51. Shakeri, following a guilty plea to robbery, spent 14 years in New York state prisons, according to the complaint. Shakeri, an Afghan national who immigrated to the United States as a child, was deported in 2008 after serving his prison sentence, the complaint says.

Prosecutors said Shakeri was at large and was believed to reside in Iran.

Two men also charged in the plots were arrested and are in custody in New York. They are Carlisle Rivera, 49, of Brooklyn, and Jonathan Loadholt, 36, of Staten Island.

The three men each face charges of murder-for-hire, conspiracy to commit murder-for-hire and money laundering conspiracy. Shakeri was also charged with providing material support to a foreign terrorist organization, identified as the Revolutionary Guard, and conspiring to do so, as well conspiracy to violate U.S. sanctions on Iran.

Rivera and Loadholt were each presented before a federal magistrate judge in Manhattan on Thursday and ordered to be detained pending trial. Their lawyers did not respond to requests for comment.

Shakeri’s time in prison overlapped with Rivera, who was convicted in 1994 of second-degree murder, the complaint says.

The document also says that beginning in September, Shakeri, who was in Tehran, spoke voluntarily by telephone with FBI agents on five dates, including as recently as Thursday. His stated reason for agreeing to be interviewed, the complaint said, was to seek a sentence reduction for another federal prisoner.

Shakeri told the FBI that he was directed to provide a plan within seven days to kill Trump during a meeting with a Revolutionary Guard official on Oct. 7. The official told Shakeri that if he could not, the Revolutionary Guard would pause until after the U.S. presidential elections, according to the complaint.

Shakeri said the official told him that Trump would lose and that afterward “it would be easier to assassinate” him, according to the complaint.

Damian Williams, the U.S. attorney for the Southern District of New York, said: “This has to stop. Today’s charges are another message to those who continue in their efforts — we will remain unrelenting in our pursuit of bad actors, no matter where they reside.”

The Associated Press contributed to this report.