The BBC Breakfast presenter Naga Munchetty breached the broadcaster’s editorial guidelines after she criticised racist comments by Donald Trump about the backgrounds of four female politicians, the corporation has ruled.

In July Trump tweeted that congresswomen Ilhan Omar, Alexandria Ocasio-Cortez, Rashida Tlaib and Ayanna Pressley should “go back to the totally broken and crime infested places from which they came”. All four are US citizens and only Omar was born overseas.

The following day BBC Breakfast invited a Trump supporter on air to defend him, prompting Munchetty to discuss the US president’s use of loaded terms.

“Every time I have been told, as a woman of colour, to go back to where I came from, that was embedded in racism,” the BBC journalist told viewers in July. “Now, I’m not accusing anyone of anything here, but you know what certain phrases mean.”

Her co-host, Dan Walker, asked her how she felt when she heard the president use such language. She replied: “Furious. Absolutely furious and I can imagine lots of people in this country will be feeling absolutely furious a man in that position thinks it’s OK to skirt the lines by using language like that.”

Munchetty suggested that Trump’s use of such language encouraged others to use it before adding: “Anyway, I’m not here to give my opinion.”

BBC Breakfast (@BBCBreakfast) "I've been told as a woman of colour to 'go home'..."@BBCNaga shares her experience as we discuss the reaction to comments made by President Trump. pic.twitter.com/u0HL5tEdgt

The clip of their brief discussion went viral, with the BBC’s own accounts pushing it out on social media where it reached hundreds of thousands of people. But after a viewer complaint the corporation’s complaints unit decided that Munchetty had gone too far in expressing a personal opinion while broadcasting in her capacity as a BBC journalist.

A BBC spokeswoman said the complaints unit “ruled that while Ms Munchetty was entitled to give a personal response to the phrase ‘go back to your own country’ as it was rooted in her own experience, overall her comments went beyond what the guidelines allow for”.

Last week the same complaints unit found that the Newsnight presenter Emily Maitlis had overstepped the mark during a discussion involving the Spectator columnist Rod Liddle, after a viewer complained she had been “sneering and bullying” towards the rightwing journalist.

The complaints unit concluded that the “persistent and personal nature of the criticism risked leaving her open to the charge that she had failed to be even-handed”.