LONDON (Reuters) - Russian news channel RT broke the UK broadcasting code when it presented tweets and emails sent by its own staff as coming from viewers of a current affairs program, British media regulator Ofcom said.

Ofcom is already investigating RT to see whether it breached impartiality rules in its reporting following an attack on a former Russian spy in Britain, and has warned its producer TV Novosti it could lose the right to broadcast in Britain.

RT said on Monday the mistakes made on the program hosted by former Scottish First Minister Alex Salmond simply reflected teething problems, adding that it had “grave concern” about Ofcom’s conduct.

RT also said Ofcom had not sufficiently considered its representations before the regulator made a provisional statement on the standards case in April.

“This gives rise to grave concern over the fairness of Ofcom’s process and agenda,” RT said. “The concern is heightened as Ofcom is using powers that exist for protection against serious matters to find in breach this trivial teething problem – a real sledgehammer to crack a nut.”

In the program, Salmond read out and answered questions from tweets and emails on topics such as Brexit and Donald Trump. Following a complaint, Ofcom investigated and was told by TV Novosti that four of the six tweets and emails were sent by people connected to the program or the presenter.

“We found this program broke our rules by misleading its audience,” a spokeswoman for the regulator said.

Ofcom, which is independent of the government, is still examining whether other RT coverage was sufficiently balanced. It said in April it had found an increase in programs which may have breached impartiality rules since the nerve agent attack on former double agent Sergei Skripal and his daughter the previous month.

Ofcom has previously said there was a high threshold for finding that a broadcaster was not fit to hold a license.