Arizona Sen. John McCain took to Twitter Tuesday to slam President Donald Trump’s recent “Pocahontas” comment. Trump called Massachusetts Sen. Elizabeth Warren “Pocahontas” at at event Monday honoring Navajo veterans.

“Our nation owes a debt of gratitude to the Navajo Code Talkers, whose bravery, skill & tenacity helped secure our decisive victory over tyranny & oppression during WWII,” McCain wrote. “Politicizing these genuine American heroes is an insult to their sacrifice.”

Trump referred to Warren as "Pocahontas" at the Monday event, sparking widespread controversy. 

“I just want to thank you because you are very, very special people,” Trump said at the event. “You were here long before any of us were. Although, we have a representative in Congress who has been here a long time … longer than you – they call her Pocahontas!”

He has long referred to Warren as “Pocahontas,” and at one point during the 2016 presidential election referred to her as “the Indian.” The remarks started after he questioned Warren’s comments about her Native American ancestry.

"Goofy Elizabeth Warren, sometimes referred to as Pocahontas, pretended to be a Native American in order to advance her career," Trump tweeted in June 2016. "Very racist!" 

Warren herself said she was shocked by Trump’s remark.

“There he was, at a ceremony to honor Native Americans, men who have really put it all on the line to save American lives, to save lives of people, our allies, during World War II, really amazing people,” she said in an appearance on CNN. “And President Trump couldn’t even make it through a ceremony to honor these men without throwing in a racial slur.”