International tech giant Microsoft has said it has detected cyber-attacks targeting a range of people involved in the US presidential election.

The company said hackers with ties to Russia, China and Iran are behind the attacks on officials from both sides of the campaign.

Strontium, the Russian hackers that breached the Democratic campaign in 2016 are again involved, with Microsoft warning that it is “clear that foreign activity groups have stepped up their efforts” targeting the election.

The group, also known as ‘Fancy Bear,’ is believed to have targeted more than 200 organisation linked to both campaigns.

The Chinese Group Zirconium has targeted high-profile people associated with Democratic nominee Joe Biden’s campaign, while Iranian group Phosphorus has targeted people associated with President Trump.

Mr Biden’s campaign said it was aware a foreign actor had tried and failed to access non-campaign email accounts of individuals working with it.

Microsoft said the majority of the attacks were “detected and stopped.”

The company said increased federal funding is needed if individual US states are to protect their electoral infrastructure from foreign interference.