MOSCOW — Russia’s main English-language satellite network complained on Monday that its British bank was abruptly closing its accounts. The network, which reported on the decision, called it a British-government-sanctioned attempt to interfere with freedom of speech.

It was the latest controversy for the network, RT, originally and still commonly known as Russia Today. The broadcaster presents itself as an alternative to the Western media, but critics call it a Kremlin-financed mouthpiece that seeks to create an alternative to reality.

“Long live freedom of speech!” Margarita Simonyan, the editor in chief of RT, wrote sarcastically on Twitter, adding that the bank had offered no explanation for the step.

The network released a letter from the bank, NatWest, telling the broadcaster to take its business elsewhere. In the letter, the bank said that it would stop serving RT on Dec. 12, that the decision had come after “careful consideration” and that it was not subject to appeal. (The broadcaster initially reported that its accounts had been frozen, but it later clarified that the bank was closing the accounts, not freezing them, and that RT was still able to withdraw its money.)