Navajo Nation President Russell Begaye on Tuesday said he believed President Donald Trump’s use of the name “Pocahontas” to refer to Sen. Elizabeth Warren (D-MA) is an ethnic slur.

“I feel that the way it was used, yes, it was,” Begaye told CNN’s Alisyn Camerota, who had asked if he considered the attack an “ethnic slur.” “Pocahontas is a real person. It’s not a caricature, it’s not someone that’s just made up. This is a person, a young lady, a Native American woman that played a critical role in the life of this nation, and to use that person in that way is unnecessary and it’s being culturally insensitive.”

The White House has said assertions that the attack is racist are “ridiculous.”

Three Navajo Code Talkers — World War II veterans Fleming Begaye Sr., Thomas Begay and Peter MacDonald — stood beside Donald Trump Monday as he called Warren “Pocahontas,” an attack referencing her previous claims, without evidence, that she had Native American heritage.

Those claims were first used to attack Warren in her bid for the Senate in 2012. Trump revived the attack in 2016, adding “Pocahontas,” in 2016.

“This was a day when the Code Talkers were being honored,” Begaye said on CNN. “They’re war heroes that helped put an end to the war. We are enjoying freedom today as it is because of their work, because of what they did, their sacrifices. Some of them did not return. Some of those that were there with us in the oval office yesterday, they were injured there on the islands when they were there in the campaign.”

“This was a day to honor them, and to insert something like that, the word Pocahontas as a jab to a senator, that belongs on the campaign trail. It doesn’t belong in the room when our war heroes are being honored.”

He added later: “When you’re in the midst of great heroes, you need to respect them and leave everything else aside and just honor them and thank them.”

Sen. John McCain (R-AZ), the chairman of the Senate Armed Services Committee, added his voice shortly afterward:

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. Politicizing these genuine American heroes is an insult to their sacrifice. — John McCain (@SenJohnMcCain) November 28, 2017

This post has been updated.