The FBI has launched an investigation into allegations from the Trump campaign that it was targeted by hackers allegedly working for the Iranian government.

In a brief statement released on Monday, the agency confirmed that it is investigating the matter, though it did not specifically name former President Donald Trump or Iran.

A spokesperson for the Trump campaign told the BBC that the documents in question were illegally obtained by foreign sources “hostile to the United States.” However, Iranian officials have denied any involvement in the hack, and the U.S. government has not formally accused Iran.

The FBI is also examining whether the same Iranian hackers targeted the Biden-Harris campaign, according to CBS News, citing sources familiar with the investigation. This comes after a report from Microsoft indicated that Iranian hackers attempted to infiltrate the campaign of an unnamed U.S. presidential candidate in June. Microsoft’s Threat Analysis Centre (MTAC) reported that a spear-phishing email—a malicious message disguised as legitimate—was sent to the campaign.

On Saturday, Trump stated that the hackers were “only able to get publicly available information.” The FBI reportedly began its investigation in early summer after both the Trump and Biden-Harris campaigns experienced attempted phishing attacks.

The Washington Post reported that three members of the Biden-Harris campaign were also targeted by phishing emails shortly before President Joe Biden announced his decision to exit the race. A Harris campaign spokesperson said that while the campaign is vigilant against cyber threats, they are “not aware of any security breaches.”

The FBI’s probe into the hacking attempts was first opened in June, according to reports. Democratic Congressman Adam Schiff has called on the FBI to disclose what it knows about the hacking attempts, warning that the intelligence community “moved much too slow” in identifying the Russian hacking and dumping scheme during the 2016 election. He urged the FBI to act swiftly in this case.

Meanwhile, Democratic Congressman Eric Swalwell has requested a briefing from the Department of Homeland Security on the alleged hack of Trump’s presidential campaign. He emphasised that while Trump is “the most despicable person ever to seek office,” foreign interference in U.S. elections cannot be tolerated.

This investigation follows warnings from U.S. security sources of an Iranian plot to assassinate Trump, unrelated to an attempted shooting in Pennsylvania last month. Additionally, the U.S. Department of Justice recently charged a Pakistani man with alleged ties to Iran in connection with a plot to assassinate U.S. officials, potentially including Trump.