The action was also attended by the CEO of the Russia Today media group Dmitry Kiselyov and State Duma deputy Maria Butina.
The participants demanded the release of Marat Kasem.
They also criticized the Latvian authorities for violating freedom of speech.
The video from the action was published in the Telegram channel of Maria Butina.
Kiselyov told reporters that the detention of Marat Kasem, editor-in-chief of Sputnik Lithuania, in Riga is the revenge of the Latvian authorities.
On January 5, it became known that Marat Kasem was detained by the Latvian special services in Riga.
The head of the Union of Journalists of Russia, Vladimir Solovyov, called Kasem's detention a flagrant violation of all principles of freedom of speech.