Two Chinese sisters who have asked President Obama and Chinese President Xi Jinping to help their father, Zhang Lin – jailed for advocating for an education for his youngest daughter – have expanded their plea.

According to Amnesty International, Zhang Lin, a veteran activist, is in prison for his “peaceful activism defending his daughter’s right to education.”

The daughters, Zhang Anni, 10, and Zhang Ruli, 19, moved to the United States as their father’s case was pending in China. The girls have been staying in the home of Reggie Littlejohn, founder of Womens Rights Without Frontiers, and her husband, Robert.

The open letter from the daughters was released through WRWF, asking world leaders to intervene as the Chinese president visits Europe this week to talk about nuclear security and build economic relationships.

Reggie Littlejohn said she joins the daughters of “courageous activist Zhang Lin in demanding his immediate and unconditional release from illegal detention.”

“He has done nothing wrong by standing up for the right of his young daughter Anni to go to school. It is unconscionable that he and three others are detained in Chinese prisons for defending the right of this precious little girl to get an education.”

The text of the girls’ letter, translated from Chinese, explains how their father was detained and is being held.

“He did not do anything wrong,” they wrote.

Amnesty International reported that in February 2013, police in Hefei, capital of the eastern Anhui province, took Zhang Anni from school and detained her.

She, at the age of 10, was whisked away and grilled by police. Deprived of food and water for 20 hours, she was given the unwanted title of “China’s youngest political prisoner.”

Earlier, the sisters wrote an open letter to Obama, Xi Jinping and others, explaining their father was “accused of ‘gathering a mob to disturb public order.'”

But they insisted the charge is groundless.

“We call on and urge United Nations Secretary-General Ban Ki-moon, U.S. President Barack Obama, President Xi Jinping and other heads of state, parliaments, and human rights organizations to pay attention to this blatant human rights abuse. Your attention could cause our father to be released!”

They explained that after Anni was detained by “four male strangers,” their father demanded justice.

However, he and other relatives, including uncles Yao Cheng, Li Huaping and Zhou Weilin, all were detained.

“We are living a free life in Reggie’s home in the United States, but our father and our uncles still cannot see the light of the day from their Chinese prison,” they wrote.

The sisters noted their father’s previous jail terms all have been for his decision to follow “the path of democracy.”

The sisters said that at a hearing for their father last December, witnesses did not tell the truth.

“We appeal to get your attention,” they wrote in the newest letter.

Reggie Littlejohn said the girls are remarkable personalities, and it is her delight to be able to help the family of Zhang Lin.

“My husband and I are very proud of Anni,” she said. “She is a smart and determined girl. In her first three months in the United States, Anni has been attending school, learning English quickly, making strides in her piano lessons and has learned to swim. She also has a quick sense of humor and a magnetic personality. She will be a leader one day. We are just getting to know Ruli, and are already impressed with her intelligence, sensitivity and insight. We have no doubt that she will be a force for good in the world.”

In April, Littlejohn said in a Web posting that the case highlights the “bold contempt for the Chinese Communist Party’s brutal persecution of the children of dissidents.”

She said at the time that the decision by China to arrest and interrogate young children amounts to “state-sponsored child abuse.”

China Aid Association, which previously publicized the “persecution of the Zhang family” through an online petition, said Zhang has been held in Bengbu.

The group explained how the 50-year-old veteran of the 1989 pro-democracy movement in Anhui is suspected of being involved in the “New Citizens’ Movement,” which is described as a peaceful cultural, social and political campaign.

Amnesty explains the charge of “gathering a crowd to disrupt order in a public place” applies to people who gathered to disturb order at railway stations or bus terminals, wharves, civil airports, marketplaces, parks, theaters, cinemas, exhibition halls and other locations.

The sisters explained that Littlejohn got in got involved because friends contacted the Women’s Rights Without Frontiers organizations, “hoping that she could shelter Anni and allow her to go to school.”

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