The regulator said that it was minded to consider imposing a ‘statutory sanction’ on RT, formerly known as Russia Today, after finding it guilty of seven breaches of the broadcasting code over coverage of the Skripal poisoning case in Salisbury.
Ofcom has the power to revoke the licence of a broadcaster if it deems it necessary.
Among other punishments Russia Today could face are directions to not repeat a programme or broadcast a correction, or a fine.
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.
RT announced in August that the Alex Salmond Show would continue despite the allegations of harassment against Mr Salmond, which he strongly denies.
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.
Seven programmes in Russia Today (out of ten investigated) were found to have breached rules on impartiality for the way they covered the poisoning of Sergei Skripal and his daughter.
A spokeswoman said: ““Our investigations found that RT failed to maintain due impartiality in seven news and current affairs programmes over a six-week period.
“Taken together, these breaches represent a serious failure to comply with our broadcasting rules.
“We have told RT that we are minded to consider imposing a statutory sanction for these breaches. The broadcaster now has the opportunity to make representations to us, which we will consider before proceeding further.”
In a submission to Ofcom, RT argued: “Audiences will not be ambushed by views aired on RT, and will not lack the context in which to evaluate them. RT is not a British broadcaster. Viewers turn to RT with the expectation that they will receive a Russian viewpoint.”
Culture Secretary Jeremy Wright said: “RT’s mask as an impartial news provider is clearly slipping. We know some foreign regimes will use any vehicle at their disposal to sow discord in the West.
“It is vital that as a society we remain vigilant to the spread of harmful disinformation and Ofcom has strong powers to tackle it where it occurs in broadcast news.”
A Russia Today spokesperson said: “RT is extremely disappointed by Ofcom’s conclusions in what were almost all self-initiated investigations into RT by the regulator. We operate under rules outlined by the regulator, and always strive to abide by them.
“It appears Ofcom has failed to fully take on-board what we said in response to its investigations and, in particular, has not paid due regard to the rights of a broadcaster and the audience. We are reviewing the findings Ofcom has put forward and will decide shortly the nature of our next steps.”