Cyrillic Letters in URL

[eluser]mDonchev[/eluser]
Hello guys,

I have an error like this : The URI you submitted has disallowed characters.

I know the regex in the config which is limiting this, but can you tell me what I should write in that regex so that I can use cyrillic letters in my URL?

My site is UTF8 if that matters.

Thanks in advance
Martin