Plenty of reports on the net.
Here’s a few and I’ll start with Russia’s typical denial:
https://tass.com/politics/1504585
https://www.cbsnews.com/news/ukraine-russia-filtration-camps-human-rights-watch/
Is that a joke? I didn’t see any evidence in the first two links. There are a couple anecdotes in the last article. I’m sure there’s all kinds of unpleasantness in such camps (and in corresponding Ukrainians camps), but I don’t see much to justify the usual propaganda out of the Capitol District.