WASHINGTON – Sen. Elizabeth Warren apologized Wednesday for "not having been more sensitive about tribal citizenship" after The Washington Post published a 1986 Texas bar registration card where she listed her race as "American Indian."

"I'm not a tribal citizen," the Massachusetts Democrat told reporters. "My apology is an apology for not having been more sensitive about tribal citizenship and tribal sovereignty. I really want to underline the point, tribes and only tribes determine tribal citizenship."

It was at least the third time in a week that Warren – who is part of the large Democratic field running to unseat President Donald Trump in 2020 – has apologized for her past self-identification.

"I can’t go back," Warren told the Post in response to the story about her Texas bar registration. "But I am sorry for furthering confusion on tribal sovereignty and tribal citizenship and harm that resulted."

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The former law school professor also apologized to the Cherokee Nation – from which she claimed to descend – in a phone call with tribal chief Bill John Baker last week for her public release of a DNA test, which an expert said was "strong evidence" that she had Native American ancestry.

But the test showed that Warren's Native American ancestor dated back six generations to 10 generations. Critics mocked her for using such a distant connection to claim to be of Native American descent, and her use of the test infuriated prominent members of the Cherokee Nation.

After Warren unveiled the results in October via an online video, Cherokee Nation Cherokee Nation Secretary of State Chuck Hoskin Jr. said in a statement that using "a DNA test to lay claim to any connection to the Cherokee Nation or any tribal nation, even vaguely, is inappropriate and wrong."

Warren said she told Baker that she was sorry for "extending confusion" about tribal citizenship" and for "harm caused."

On Wednesday, Warren did not deny that there could be other documents out there on which she identified herself as Native American.

"All I know is, during this time period this is consistent with what I did because it was based on my understanding from my family's stories. But family stories are not the same as tribal citizenship and this why I have apologized," she said.

When asked how voters will react to the news, Warren said she would leave that up to the political pundits.

"But understand, this is from the heart. This is about my family, my brothers, and it is about an apology from the heart," she said.

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Warren's claim to Native American heritage is an issue that has dogged her since her 2012 Senate campaign against former Republican Sen. Scott Brown. Her opponents have accused her of using minority status for professional benefit and Trump has mocked her as "Pocahontas."

But a Boston Globe investigation revealed that Warren identified herself as white when she applied to teach law at the University of Pennsylvania in 1987 and when she applied in 1995 to work at Harvard University. At both institutions, she changed her ethnicity to Native American after she had already started working there.

"Nothing about my background ever had anything to do with any job I got in any place. It's been fully documented," she told reporters Wednesday.

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