  The Russian invasion of Ukraine in February 2022 was accompanied by practices
of information warfare, yet existing evidence is largely anecdotal while
large-scale empirical evidence is lacking. Here, we analyze the spread of
pro-Russian support on social media. For this, we collected N = 349,455
messages from Twitter with pro-Russian support. Our findings suggest that
pro-Russian messages received ~251,000 retweets and thereby reached around 14.4
million users. We further provide evidence that bots played a disproportionate
role in the dissemination of pro-Russian messages and amplified its
proliferation in early-stage diffusion. Countries that abstained from voting on
the United Nations Resolution ES-11/1 such as India, South Africa, and Pakistan
showed pronounced activity of bots. Overall, 20.28% of the spreaders are
classified as bots, most of which were created at the beginning of the
invasion. Together, our findings suggest the presence of a large-scale Russian
propaganda campaign on social media and highlight the new threats to society
that originate from it. Our results also suggest that curbing bots may be an
effective strategy to mitigate such campaigns.
