[FabHK]

For what it's worth, there is also a Sinitic language fairly close to Mandarin that's written in Cyrillic characters, Dungan (which, incidentally, sort of refutes the notion that one can only write Chinese languages with Chinese characters).

https://en.wikipedia.org/wiki/Dungan_language

http://languagelog.ldc.upenn.edu/nll/?p=4578