China, Russia and Iran have rejected accusations by software giant Microsoft that hackers from their countries are targeting US presidential campaigns ahead of the November elections.
A Chinese Foreign Ministry spokesman suggested on Friday that Microsoft and the United States were inventing the allegations.
"With regard to the US elections, I have repeatedly said the US elections are an internal matter and we have no interest or intention of interfering."
A spokesman for Iran's Foreign Ministry made a similar statement on Friday, saying that it didn't matter to Tehran who won the election, while Kremlin spokesperson Dmitry Peskov said that Microsoft's conclusions didn't require attention as long as there was no proof, according to the TASS news agency.
The countries listed by the Seattle-based company match assessments made by the US intelligence community.
Microsoft said the attacks from China appeared to target Democratic nominee Joe Biden's campaign and affiliated organisations, in addition to groups like think tanks which focus on foreign policy.
The China-based group also went after "one prominent individual" formerly linked to Trump.
The Russian hackers appear to be linked to groups that operated in 2016, Microsoft said.
The hackers were going after consultants working for both Republicans and Democrats, US think tanks, the European People's Party and political parties in Britain.
The Iranian hackers tried to target the Trump White House and the president's campaign, but failed.
The official US intelligence assessment from the White House said China favoured a Biden win over President Donald Trump, while Russia was particularly focused on tarnishing Biden.