President Donald Trump’s use of “Pocahontas” to take a jab at Sen. Elizabeth Warren during an event honoring Native American veterans Monday sparked outrage among politicians.

Trump has referred to Warren as “Pocahontas” several times since she made unverified claims during her 2012 Senate race that she has Native American heritage. Warren, a Democratic senator from Massachusetts, fired back at Trump moments after his comments Monday.

“It is deeply unfortunate that the president of the United States can’t make it through a ceremony honoring these heroes without having to throw out a racial slur,” Warren said during an appearance on MSNBC.

WATCH: Elizabeth Warren responds to Trump's "Pocahontas" remark on @MSNBC:



"It is deeply unfortunate that the President of the United States cannot even make it through a ceremony honoring these heroes without having to throw out a racial slur." pic.twitter.com/au1QntxDzR — NBC News (@NBCNews) November 27, 2017

The president of the Navajo Nation, Russell Begaye, said Monday evening that he would not engage in the dialogue between Trump and Warren, and would instead focus on the prejudice Native Americans face.

“First and foremost, we appreciate the honor and recognition that has been bestowed upon the Navajo Code Talkers, who truly are national treasures and protectors of freedom,” Begaye said in a statement. “In this day and age, all tribal nations still battle insensitive references to our people. The prejudice that Native American people face is an unfortunate historical legacy. As Native Americans, we are proud people who have taken care of this land long before there was the United States of America and we will continue to fight for this nation.”

He concluded: “It was our Code Talkers that ensured the freedom of the United States and that’s what is important to remember here.”

Still, several of Warren’s colleagues, including Sen. Ed Markey (D-Mass.) and Rep. Raul Grijalva (D-Ariz.) condemned Trump’s remarks.

What @realDonaldTrump said about my partner @SenWarren is a slur. It disparages the Native American war heroes, standing right beside the President, who risked their lives to protect his right to make such a disgusting comment. — Ed Markey (@SenMarkey) November 27, 2017

Trump's Pocahontas remark in front of Navajo code talkers is offensive and shows his complete ignorance for Native American history during Native American Heritage Month. — Raul M. Grijalva (@RepRaulGrijalva) November 27, 2017

Tom Perez, chair of the Democratic National Committee, said Trump continued to “debase the office of the presidency” by using the racial slur during the ceremony.

This is disgusting and dishonors all Native Americans, including the large number of Native veterans who have served our country. Donald Trump owes an apology to Tribal Nations and these American heroes. https://t.co/vJY2NSQllP — Tom Perez (@TomPerez) November 27, 2017

“What Trump displayed today was an embarrassment to our values and a disgraceful insult to the heroes of our history,” Perez said in a statement. “Our country deserves better than this.”

This story is developing. Check back for updates.

Nick Visser contributed reporting.