(CNN) An American woman who has been prevented from leaving China for almost a year made an emotional plea this week for her family to be able to return home.

The Liu siblings -- Cynthia, 28, and Victor, 19 -- and their mother, Sandra Han, traveled to China in June 2018 to visit their ailing grandfather. Chinese authorities have prevented them from leaving through the use of an exit ban . All three are US citizens.

In a video obtained by CNN on Thursday, Cynthia Liu said she and her brother "wake up every morning terrified."

"After 11 months of being in a place where every twist and turn seems designed to crush our spirits so completely, we have never felt more exhausted, sad and hopeless. We hang on by a thread to our sanity and to any sliver of hope," an emotional Liu said. "We need to go home."

Liu said she and her brother have been separated from their mother by Chinese authorities and they have not seen or spoken to her "in a long time." While Liu said they can move around within China, she said she cannot work and her brother cannot go to school. The siblings' location in China is unclear.

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