US President Donald Trump is refusing to back down, despite the growing criticism of his racially-charged comments about the women.
He'd called all four of them foreign-born.
He is now calling on them to apologise for what he described as the "foul language they have used, and the terrible things they have said."
This latest storm began on Sunday when he attacked the women in tweets widely condemned as racist.
Al Jazeera's Kimberly Halkett reports from the White House.