President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE slammed the Democratic lawmaker challenging Sen. Dean Heller Dean Arthur HellerOn The Trail: Democrats plan to hammer Trump on Social Security, Medicare Lobbying World Democrats spend big to put Senate in play MORE (R-Nev.) on Saturday, dubbing Rep. Jacky Rosen Jacklyn (Jacky) Sheryl RosenHillicon Valley: Election officials prepare for new Russian interference battle | 'Markeyverse' of online fans helps take down a Kennedy | GOP senators unveil bill to update tech liability protections Google, Apple, eBay to meet virtually with lawmakers for tech group's annual fly-in Senate Democrats demand answers on migrant child trafficking during pandemic MORE (D-Nev.) "Wacky Jacky" in a fiery campaign speech.

Speaking at the Nevada state GOP convention, Trump attacked Rosen for campaigning with Massachusetts Sen. Elizabeth Warren Elizabeth WarrenDimon: Wealth tax 'almost impossible to do' CNN's Don Lemon: 'Blow up the entire system' remark taken out of context Democrats shoot down talk of expanding Supreme Court MORE (D), whom he again called the racially charged nickname "Pocahontas."

ADVERTISEMENT

"[Heller's] opponent wants to raise taxes," Trump said, to boos. "She wants to raise taxes, think of it. I mean, it's ridiculous. Should I mention her name?"

Trump paused as the crowd egged him on to say the name.

"I have a great nickname for her," Trump added. "Wacky Jacky. You don't want her as your senator."

"Wacky Jacky is campaigning with Pocahontas, you believe this? In your state!" he added.

"I have a great nickname for her... Wacky Jacky."@POTUS unleashes his nickname for @RosenforNevada. pic.twitter.com/djhTUOTb7I — Fox News (@FoxNews) June 23, 2018

Rosen responded to Trump's attacks later Saturday afternoon, dubbing her opponent a "rubber stamp" for Trump in Washington.

“The President is attacking me with lies and petty insults because I’m not afraid to stand up to him," Rosen said in a statement to The Hill. "Dean Heller has been a rubber stamp for Donald Trump in Washington, caving to the President’s divisive agenda at Nevada’s expense. This was Senator Heller’s reward for his loyalty.”

Trump has used the "Pocahontas" nickname to refer to questions surrounding Warren's claims of Native American heritage. A Washington Post fact-checker wrote in 2016 that there was "no official documentation" found to support her claims.

Heller is seen as a vulnerable Republican ahead of midterm elections, where Democrats are hoping to pick up two seats and flip the Senate. But, the Nevada lawmaker has secured Trump's support and saw a primary challenger back out of the race earlier this year at the president's urging.

Tickets for Saturday's fundraiser for Heller ranged from $15,000 to $50,000, according to an invitation obtained by CNN.

An April poll of the Nevada Senate race showed Heller leading Rosen by just 1 point, according to the Nevada Independent/Mellman Group survey.

— Updated 6:03 p.m.