Politicians appearing on a Kremlin-backed broadcaster risk being used as “propaganda tools”, the Prime Minister has told the House of Commons.
Former Scottish First Minister Alex Salmond is an example of such a politician, as he still has his own show on RT, despite pressure from SNP chiefs to reconsider.
The issue was raised at Prime Minister’s Questions on Wednesday by Scottish Conservative MP John Lamont, linking the broadcaster to the Salisbury attacks.
The MP for Berwickshire, Boxburgh and Selkirk said: “Given what we know about the Russian state's involvement in the Salisbury poisonings, does the Prime Minister think it appropriate that parliamentarians both current and former appear on Russian state television?"
Mrs May responded: "I'm sure we all have doubts about the objectivity of the reporting on RT, which does remain a tool of propaganda for the Russian state.
"Decisions about going on RT are a matter for the judgment of each individual, but they should be clear that they risk being used as a propaganda tool by the Russian state."
The Prime Minister acknowledged SNP Westminster leader Ian Blackford had also said people should not appear on RT and added the same applied to Iranian state broadcaster Press TV, which was recently invited to a Labour constituency meeting.
She added: "I would also say the same applies to Press TV, whose licence to broadcast in the UK has been revoked by Ofcom."
This comes as a Russian man wanted for the novichok poisoning of the Skripals says he will comment on the case next week.
Russian state TV made the announcement, but it has not been specified which of the two men identified as suspects would speak.
President Putin announced on Wednesday that they had identified the two men suspected of the Salisbury poisoning.
Mr Putin said there is "nothing criminal" about the suspects who were identified by the UK as Russian military intelligence officers Alexander Petrov and Ruslan Boshirov.