Comedy writer Katie Rich has been suspended from NBC's late night comedy show Saturday Night Live after tweeting that Barron Trump, the youngest son of Donald Trump, would become America's "first homeschool shooter".

Rich, who has been suspended indefinitely, deleted the original tweet shortly after it provoked a backlash on the social media site during President Trump's inauguration on 20 January. Three days later the comedy writer issued an apology.

"I sincerely apologise for the insensitive tweet. I deeply regret my actions and offensive words. IT was inexcusable and I am so sorry," Rich tweeted on her personal account which had been temporarily deactivated.

Anonymous sources, who were not authorised to brief the press, told the LA Times Rich had been suspended immediately from Saturday Night Live (SNL) following her comments directed at Barron.

The tweet has marked a nadir both in relations between Trump and SNL and for attacks on the president's 10-year-old son.

Trump has regularly attacked the comedy show and actor Alec Baldwin, taking twitter to call the programme "sad" for its portrayal of his unique public speaking style.

Most recently SNL lampooned the president and his close relationship with Russian premier. Amid accusations of Russian hackers influencing the presidential election in Trump's favour, actor Beck Bennett playing Vladimir Putin mocked: "I promise that we will take care of America. It is the most expensive thing we have ever bought."

Barron Trump has garnered media attention following his father's election in November. Barron appeared on stage during Trump's acceptance speech in New York where he was said to look tired.

Rich is not the first comedian to stir controversy on twitter mentioning Barron. US media personality Rosie O'Donnell, who has a long-running feud with Donald Trump, suggested on social media that Barron might have autism.

O'Donnell later explained her own daughter had been diagnosed with high-functioning autism and added she had hoped to bring attention to autism in children.