The Russian telecommunications authority Roskomnadzor said it had sent a letter to YouTube demanding an end to the suspension, seeing it as "an act of censorship which is contrary to the Russian Constitution".
"These destructive actions (...) are unprecedented and violate the essential principle of free dissemination and access to information," she added.
YouTube suspended the account of RT's recently launched German-language "Auf Sendung" (On Air) channel on Thursday.
However, this streaming channel can still be watched on the German RT site.
The American platform justified this blockage by the fact that the launch of this German channel was an attempt to bypass previous terminations, last September.
YouTube, owned by Google, had indeed suspended RT channels in Germany, after warning, for violating its guidelines in the fight against disinformation about Covid-19.
This decision angered Moscow, which accused Berlin of having a hand in the ban, at a time when diplomatic relations between Germany and Russia were strained.
Berlin had denied being at the origin of these decisions.
The latest suspension came the day after the dismissal of two Russian diplomats by Germany after German justice ruled that the murder of a Chechen opponent in Berlin in 2019 was ordered by Moscow.
Launched in 2005 as "Russia Today", state-funded RT has grown with broadcasters and websites in multiple languages, including English, French, Spanish and Arabic.
She has sparked controversy in many countries, notably in the United States, where she had to register as a "foreign agent", and in Great Britain, where authorities threatened to withdraw her broadcasting license. .
The channel has been banned in several countries, notably in Lithuania and Latvia.
© 2021 AFP