Microsoft said Thursday it detected and thwarted cyberattacks in recent weeks from China and Russia targeting US presidential campaign staff.

The attackers have been targeting staff from the campaigns of President Donald Trump and Democratic nominee Joe Biden, Microsoft said in a security blog.

“In recent weeks, Microsoft has detected cyberattacks targeting people and organizations involved in the upcoming presidential election, including unsuccessful attacks on people associated with both the Trump and Biden campaigns,” said corporate vice president Tom Burt.

“The activity we are announcing today makes clear that foreign activity groups have stepped up their efforts targeting the 2020 election as had been anticipated, and is consistent with what the US government and others have reported.”