Pre-trained sentiment_twitter always returns negaive for Ru

Sorry, a total newbie here.
I just tested the ready-made docker image and tried to use sentiment_twitter model. It works just fine with English, but for any Russian input it always returns ‘negative’ whatever is written there.
What am I doing wrong?

An example of request (that returns negative)

curl -X 'POST' \
  '' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "x": [

Dear @chapkovski , Thank you very much for your interest!

sentiment_twitter is intended to classify only English utterances. For Russian you can use this configuration file.

We keep working on multilingual sentiment model. We hope to ship it in our next release. Please let me know if you need further assistance.