Ofcom ruled in December that the RT news channel, formerly Russia Today, was not impartial in seven news and current affairs programmes which aired in the UK over a six-week period.
The programmes were mostly about the Skripal poisoning or the conflict in Syria.
Now RT, which hosts Alex Salmond’s chat show, has issued a statement saying that it “will be seeking judicial review of Ofcom’s decisions and process in its breach findings... against the network”.
It added: “We firmly believe that none (of the programmes) were in breach.
“RT is left with no choice other than to seek judicial review of the matter.”
It said: “None of the seven in-breach decisions against RT concluded that we had disseminated inaccurate information.
“Ofcom’s own analysis acknowledged that the network presented multiple sides in its news coverage and discussion.”
It said that its “alternative viewpoints are essential to a well-informed public debate” and that the regulator had “breached a key right of broadcasters, and more importantly of audiences.
“We are now placing the matter in the hands of the courts.”
But an Ofcom spokeswoman said: “We will defend our assessment, which followed a thorough investigation under our rules.”
Diplomatic relations between the UK and Russian governments hit a new low following the poisoning of Russian ex-spy Sergei Skripal and his daughter Yulia in Salisbury, Wiltshire, in March.
Ofcom said RT failed to give due weight to a wide range of voices on a matter of major political controversy.
Possible penalties could include the broadcaster being fined or even having its licence revoked.
RT’s licensee TV-Novosti alleged that Ofcom was under intense pressure from the UK Government, which the watchdog has strongly denied.
After Ofcom’s ruling, Russia’s media watchdog launched an investigation into the BBC’s websites and World News channel over alleged violations of Russian law.
Ofcom previously censured RT after an edition of the Alex Salmond Show breached rules for claiming messages to the show had come from viewers when in fact they were sent by production staff.
Former First Minister Alex Salmond faced a backlash from politicians of all parties after agreeing to host a chat show on the Kremlin-backed channel in 2017.
Mr Salmond was accused of becoming a ‘useful idiot’ for Vladmir Putin’s regime.
Prime Minister Theresa May has previously warned that politicians appearing on RT risk being used as “propaganda tools”.
Two of the seven RT programmes featured former MP George Galloway.