Activist Rachel Dolezal has resigned from her post at the country's leading African-American advocacy group amid allegations she is a white person masquerading as being black.

The resignation from her senior role at the National Association for the Advancement of Coloured People (NAACP) came as her parents — who are white and say she is too — urged her to seek counselling.

Ms Dolezal, 37, built a career as an activist in the black community of Spokane, Washington.

She rose to become president of the Spokane branch of the NAACP, and served as an independent mediator for the city's police force.

Neither position required that she be black, but media reports said Ms Dolezal identified herself in application forms and in public appearances and writings as black.

In her resignation letter, she wrote that her commitment to the "racial and social justice movement" remained undiminished, but "the dialogue has unexpectedly shifted internationally to my personal identity in the context of defining race and ethnicity".

She did not directly address her race in the letter, and dodged questions seeking clarification about her race and ethnicity — breaking off an interview with a local TV reporter when asked point blank: "Are you African American?"

Ms Dolezal allegedly resigned under pressure from the NAACP.

Leaders from the city of Spokane said in a statement that they were "disappointed" over the episode and "the alleged misrepresentation".

Parents baffled by daughter's actions

Prior to her resignation, her parents Lawrence and Ruthanne Dolezal said they were baffled by what their daughter had done, adding they had known for years but kept it quiet until reporters recently began asking them questions.

Since the story broke, her parents provided local media with a birth certificate and photographs of Ms Dolezal as a blonde, fair-skinned child.

Now, as an adult, she is tawny-skinned and dark-haired.

"Rachel is trying to reject her own reality, her own identity and by doing that she does not alter reality," her mother said, adding that if she had the chance to speak to her daughter now she would urge her to get help.

Several US media outlets reported that Ms Dolezal sued historically black Howard University — from where she holds a degree — in 2002 for racial discrimination because she was white.

Her parents, who adopted four black children, said their daughter had always been interested in issues of ethnicity and diversity.

But around 2007, they learned from a newspaper article she was claiming to be African-American.

At that point, she had already severed contact with her parents.

AFP