According to a New Scientist report, Russia and China are using artificial intelligence to stage relentless cyberattacks against the UK. The main effect highlighted is speed: AI is increasing the pace at which attacks are directed at UK infrastructure.
The same report notes that AI is not only an offensive tool. It is also being used on the defensive side, helping to protect against the very attacks it enables.
This summary is based on a single source, so the claims should be treated as one outlet's reporting rather than independently verified findings.