WASHINGTON (AP) — The Justice Department is preparing criminal charges in connection with an Iranian hack that targeted Donald Trump’s presidential campaign, two people familiar with the matter said Thursday.

It was not immediately clear when the charges might be announced or whom precisely they will target, but they would be the result of an FBI investigation into an intrusion that investigators across multiple agencies quickly linked to an Iranian effort to influence this year’s U.S. presidential election.

The prospect of criminal charges comes as the Justice Department has warned about countries including Russia and China seeking to meddle in the presidential election between Trump and Democratic nominee Kamala Harris, including by hacking and using covert social media campaigns designed to shape public opinion.

Iran “is making a greater effort to influence this year’s election than it has in prior election cycles and that Iranian activity is growing increasingly aggressive as this election nears,” Assistant Attorney General Matthew Olsen, the Justice Department’s top national security official, said in a speech Thursday in New York. “Iran perceives this year’s elections to be particularly consequential in impacting Iran’s national security interests, increasing Tehran’s inclination to try to shape the outcome.”

The Trump campaign disclosed on Aug. 10 that it had been hacked and said Iranian actors had stolen and distributed sensitive internal documents. At least three news outlets — Politico, The New York Times and The Washington Post — were leaked confidential material from inside the Trump campaign. So far, each has refused to reveal any details about what it received.

Politico reported that it began receiving emails on July 22 from an anonymous account. The source — an AOL email account identified only as “Robert” — passed along what appeared to be a research dossier the campaign had apparently done on the Republican vice presidential nominee, Ohio Sen. JD Vance. The document was dated Feb. 23, almost five months before Trump selected Vance as his running mate.

The two people who discussed the looming criminal charges spoke on condition of anonymity to The Associated Press because they were not authorized to speak publicly about a case that had not yet been unsealed.

The Washington Post first reported that charges were being prepared.