Moscow (CNN)BBC's Russian-language website is being investigated by Russia's telecommunications regulator Roskomnadzor for possible "terrorist content."
Roskomnadzor said Thursday it would probe whether the British public broadcaster was in violation of Russia's strict anti-extremism laws.
"At present, materials have been discovered that broadcast the ideological attitudes of international terrorist organizations (quotes from terrorist Al-Baghdadi)," Roskomnadzor said, referring to ISIS leader Abu Bakr al-Baghdadi.
"An examination is carried out to determine whether these materials comply with Russian anti-extremist legislation."
Responding to the allegations, a BBC spokesperson told CNN: "As a global broadcaster, BBC fully complies with the legislation and regulations of every country where it operates, including Russia, and we are always ready to provide additional information about our coverage when requested by the appropriate regulator."
Russia has anti-extremism laws that observers say have strong potential to stifle political speech. As a matter of practice, Russian news organizations refer to ISIS as an organization that is outlawed in the Russian Federation, a disclaimer not used by foreign media outlets.
Roskomnadzor in December said it would open a probe into the BBC's compliance with Russian law after Britain's media regulator, Ofcom, ruled that state-owned Russian network RT's coverage of the Salisbury poisonings breached impartiality rules.
Ofcom said the Russian broadcaster failed to preserve "due impartiality" in seven programs that aired after the poisoning of former Russian double agent Sergei Skripal.
Roskomnadzor described the move at the time as a tit-for-tat response.