During World War II, the USA military recruited hundreds of Marines from Navajo reservations across the Southwest, tasking them with using their native language to transmit sensitive messages in combat that couldn't be intercepted and decoded by enemy forces.
Media captionThe US president makes a joke about Senator Elizabeth Warren in front of Native Americans. She was ultimately unable to prove she was Native American. "You are special people".
President Donald Trump referred to Massachusetts Sen.
"What @realDonaldTrump said about my partner @SenWarren is a slur", Markey tweeted.
The Washington Post Fact Checker found that "outstanding questions about Warren's directory listing - and her relying on family lore rather than official documentation to make an ethnic claim - certainly raise serious concerns about Warren's judgment. And the color that we have from within the room was that there was just a long, awkward silence".
In an interview with MSNBC, Mrs Warren responded: "It is deeply unfortunate that the president of the United States can not make it through a ceremony honouring these heroes without throwing out a racial slur". She says the comments should be "constantly covered". "It hasn't worked out in the past, it isn't going to work out in the future".
"I think what most people find offensive is Senator Warren lying bout her heritage to advance her career", she said.
John Norwood, general secretary of the Alliance of Colonial Era Tribes, said Trump's nickname for Warren "smacks of racism". These are men who volunteered to serve despite owing nothing more to a country that had systematically mistreated their people for centuries.
He added, "Crooked Hillary is wheeling out one of the least productive senators in the U.S. Senate, goofy Elizabeth Warren, who lied on heritage".