Sen. Elizabeth Warren made her message to President Trump clear: "Donald, you ain't seen nasty yet."

The slogan appeared on a sign at the Boston Women's March, Warren remembered.

The Massachusetts Democrat took on the president yet again at a Friday town hall in New York where she read excerpts from her book, "This Fight is Our Fight: The Battle to Save America’s Middle Class."

"Women's rights are not up for grabs," she remembered another protester's sign read.

New Poll Shows Trump Approval at 50 Percent

Bill Cosby's Spox: Tell Gloria Allred to 'Go Back to Law School'

Pirro Blasts GOP: 'You're In Power - Do Something' to Pass Trump Agenda

Warren has been one of the most vocal Democrats against the president during and after the 2016 campaign season, sparking speculation about a possible run for the Democratic presidential nomination in 2020.

"We are an army, an army filled with optimism and hope and fierce determination," Warren read from her book.

She slammed Trump on healthcare and his economic policies, saying they are hurting ordinary Americans.

Warren's comments apparently referenced Trump calling Hillary Clinton a "nasty woman" during a presidential debate.

After Trump's inauguration, actress Ashley Judd slammed Trump in a poem entitled "I Am a Nasty Woman."

NFL's Kaepernick Compares Cops to Fugitive Slave Patrols

'They Make Him Into a Saint': Watters Checks Out Trump-Caesar Play

'Crooked Hill' Street Sign Altered With 3 Additional Letters...