Sen. Elizabeth Warren doubled down on her claims to Native American heritage during a surprise appearance at the National Congress of American Indians on Wednesday, and blasted President Trump for mocking her as “Pocahontas.”

“I get why some people think there’s hay to be made here. You won’t find my family members on any rolls, and I’m not enrolled in a tribe,” Warren said.

“And I want to make something clear. I respect that distinction. I understand that tribal membership is determined by tribes — and only by tribes.”

The Massachusetts Democrat then addressed claims that she used her Native American ancestry to get minority status to boost her career, including when she taught at Harvard Law School.

“I never used my family tree to get a break or get ahead. I never used it to advance my career,” Warren insisted.

She rebuked Trump for referring to her as “Pocahontas,” including during a White House ceremony last November to honor Navajo code talkers who fought in World War II.

“We have a president who can’t make it through a ceremony honoring Native American war heroes without reducing Native history, Native culture, Native people to the butt of a joke,” Warren said in Washington.

She said her mother was born on Valentine’s Day 1912 in Oklahoma, and when she met Warren’s father, “my daddy fell head over heels in love with her.”

“But my mother’s family was part Native American. And my daddy’s parents were bitterly opposed to their relationship. So, in 1932, when Mother was 19 and Daddy had just turned 20, they eloped,” she said.

“The story they lived will always be a part of me. And no one — not even the president of the United States — will ever take that part of me away,” she said.

Warren also vowed she will be an advocate for Native Americans.

“For far too long, your story has been pushed aside, to be trotted out only in cartoons and commercials,” she said. “So I’m here today to make a promise: Every time someone brings up my family’s story, I’m going to use it to lift up the story of your families and your communities.”

Law school directories from the Association of American Law Schools from 1986 to 1995 put Warren on the association’s list of “minority law teachers” when she was teaching at the University of Texas and the University of Pennsylvania.

Warren said she listed herself with Native American heritage because she hoped to meet people with similar roots.

With Post wires