The Federal Bureau of Investigation is looking for evidence of cyberattacks from Russia and China.
The FBI said it was investigating the attacks on Iran carried out by hackers in June.
Agents are looking into details of a cyberattack carried out by Iran as part of a global scheme involving other states, The Washington Post reports.
The FBI assesses Iran as an aggressive but not overly dangerous adversary in the cyber sphere.
The United States is concerned about more thorough efforts that Russia and China may undertake.
The FBI has discovered that one of Donald Trump's most senior aides was targeted by Iranian hackers.
It was also reported that the campaign headquarters of US Democratic presidential candidate Kamala Harris was subjected to a cyberattack in July.
Following a series of cybercrimes by Iran, the FBI is investigating possible involvement of Russia and China in the cyberattacks.
