US President Donald Trump said he did not regret tweeting that four Democratic freshmen congresswomen should "go back" to their home countries, despite them all being US citizens, as he departed the White House in Washington DC for a rally in North Carolina on Wednesday.

"If people want to leave our country, they can. If they don't want to love our country, if they don't want to fight for our country, they can," Trump said. "I'll never change on that. No."

Trump said he was not "relishing the fight" with the congresswomen, but "enjoying it because I have to get the word out to the American people.

Trump addressed questions concerning the background of Rep. Ilhan Omar of Minnesota, saying "there's a lot of talk about the fact that she was married to her brother. I know nothing about it. I hear she was married to her brother."

Omar arrived to the United States in 1992 as a refugee from Somalia.

As Omar was running for a seat in the Minnesota House in 2016, conservative bloggers maintained she was simultaneously married to two men, one of which was alleged to be her brother.

These allegations have since been disproven by marriage records.

The US President sparked controversy over the weekend with a series of tweets seemingly aimed at new Democratic congresswomen Alexandria Ocasio-Cortez, Rashida Tlaib, Ayanna Pressley and Ilhan Omar that were widely condemned as racist. He wrote that the representatives - three of whom were born in the US and all American citizens - should "go back and help fix the totally broken and crime infested places from which they came."