'I'll see you in court' - Trump and Maine governor clash on trans athletes
Trump was addressing Democratic and Republican governors at the White House when the confrontation occurred.
During the exchange, Trump told Governor Mills, "You better do it because you're not going to get federal funding."
The governor responded in a statement on Friday, saying her state "will not be intimidated by the President's threats."
On 6 February, President Trump signed an executive order preventing transgender women from competing in female sports categories.