Beyond examples, it would be highly surprising if they weren't doing it. I think the burden of proof is on the person saying that they wouldn't do the thing that any sensible realist actor would do to a rival. That would be a level of bizarre incompetence that is too much to fathom.
https://www.reuters.com/investigates/special-report/usa-covi...
https://www.technologyreview.com/2021/09/16/1035851/facebook...
https://openai.com/index/disrupting-deceptive-uses-of-AI-by-...
https://en.wikipedia.org/wiki/Russia_and_Black_Lives_Matter
https://www.scmp.com/week-asia/politics/article/3266870/onli...
https://www.cnn.com/2024/07/29/politics/iran-covert-influenc...