The FBI has launched an investigation after Donald Trump’s presidential campaign alleged its internal communications were targeted by hackers working for the Iranian government.
The former president said on Saturday that Microsoft had informed his campaign that Iran had hacked one of its websites.
Trump said Iran was “only able to get publicly available information”.
“We can confirm the FBI is investigating the matter,” the FBI said in a statement on Monday, but it did not name Trump or Iran.
The Iranian government has denied that it hacked the Trump campaign.
The FBI is also investigating an alleged hack targeting advisers to the campaign of President Joe Biden and Vice President Kamala Harris, the Washington Post reported on Monday.
The FBI began the investigation in June, when Mr Biden was still running for president, suspecting that Iran was behind the attempts to steal data from two US presidential campaigns, the newspaper said, citing sources.
The Harris campaign did not immediately respond to a request for comment.
Trump’s campaign pointed to a report on Friday by Microsoft researchers that indicated that Iranian government-linked hackers tried breaking into the account of a “high-ranking official” on a US presidential campaign in June.
The report added that the hackers took over an account belonging to a former political adviser and then used it to target the official.
It did not provide further details on the targets’ identities.