President Donald Trump referred to Democrat Sen. Elizabeth Warren as “Pocahontas” while honoring Navajo World War II veterans at a White House ceremony Monday.

“You were here long before any of us were here,” Trump said about the Navajo code talkers. “Although, we have a representative in Congress who they say was here a long time ago. They call her Pocahontas.”

Trump made the remarks under a portrait of former President Andrew Jackson, who signed the Indian Removal Act.

Sen. Warren responded to Trump’s comments on MSNBC by saying that it is “deeply unfortunate that the President of the United States cannot even make it through a ceremony honoring these heroes without throwing out a racial slur.”

The Massachusetts senator has claimed she is a Native American, but has yet to ever produce documentation proving that she is.

She listed herself on the Harvard law directory as “Native American” and told a reporter in 2012 that her aunt said that Warren’s ancestors had “high cheekbones” as proof of her American Indian heritage.

Trump referred to Warren as “Pocahontas” several times on the campaign trail, which the senator claimed Monday is Trump’s way of trying to get her to “shut up.”

White House press secretary Sarah Sanders denied Monday that “Pocahontas,” the name of a famous Native American who married a colonialist, can be used as a racial slur.

“I think what most people find offensive is Sen. Warren lying about her heritage to advance her career,” Sanders said.