Proclaiming his administration as "federal law," the president demanded that Maine comply with his executive order banning transgender women from participating in women and girls' sports. Mills told the president that the state won't be intimidated and reiterated her vow to challenge him in court if he denies the state millions in federal cash.

Tenn., reacted to the public spat between Maine Gov. Janet Mills and President Donald Trump on "Fox News Live" on Sunday.

A high school track and field championship in Maine has ignited a national debate over transgender athletes competing in women's sports.