Melania Trump has been criticised for remaining silent over a series of racist tweets her husband directed towards four Democratic congresswomen of colour suggesting they should “go back” to where they came from.CNN pundits have pointed out that the first lady has been a US citizen for a shorter amount of the time than all four of the congresswomen targeted in the US president’s racist tirade.Three of the four Democratic congresswomen of colour known as “the squad”– Alexandria Ocasio-Cortez, Rashida Tlaib and Ayanna Pressley – were born and raised in the US.The fourth, Ilhan Omar, was born in Somalia and moved to the country as a child. She became a US citizen at the age of 17 in 2000.While Ms Trump was born in Slovenia and became a US citizen in 2006, a year after she married the US president.Jake Tapper, a CNN journalist, highlighted the comparison between Ms Omar and the first lady in a news report on Monday. He said that Ms Omar has “been a US citizen since she was a teenager, longer than the first lady”.However, Ms Trump has not yet commented on her husband’s racist tweets.Stephanie Grisham, the first lady's spokeswoman, tweeted on Monday: “So typical to watch the mainstream media and Dems attack @realDonaldTrump for speaking directly to the American people.“His message is simple: the USA is the greatest nation on Earth, but if people aren't happy here they don't have to stay.”Mr Trump has also been accused of hypocrisy after suggesting the four Democratic congresswomen “should go back and help fix the totally broken and crime infested places from which they came”.Speaking on CNN on Monday about Mr Trump racist tweets, political commentator Ana Navarro, said: “Melania Trump was born where – Slovenia?“How about her parents who are here through family immigration?“I’m sick of that guy’s hypocrisy, pitting people against each other."It is no coincidence that the congresspeople he is picking on are all women of colour.”The first lady previously spoke out against her husband when she condemned his zero-tolerance immigration policy that led to the separation of immigrant families at the US border.Ms Trump said that she was “heartbroken” by the removal of children from their parents and that it prompted an unannounced visit to the southern border earlier last year.“It was unacceptable for me to see children and parents separated,” Ms Trump said in an interview for ABC News’ special Being Melania. “It was heartbreaking. And I reacted with my own voice.”In his latest round of tweets, Mr Trump has demanded an apology from the Democratic congresswomen targeted by his racist comments.He doubled down on his “go back home” remarks in front of reporters in the White House, adding: “If you’re not happy here, then you can leave”