Starting in the mid-1990s, driven first by famine and now by poverty, North Koreans have been crossing the border to China in large numbers. Many are women who are taken across the border by traffickers, only to be sold to Chinese men. Of those women, some are compelled to flee again, to South Korea, either because they can’t endure their forced marriages any longer or because every day they risk being captured by Chinese authorities and repatriated to North Korea where they might face beatings, starvation and worse in prison camps. And for some, the choice to go on the run again means making the heart-wrenching decision to leave their children behind.

The journey to South Korea, crossing mainland China and through Southeast Asia, can be hazardous and physically grueling, so some women leave their children with their Chinese fathers. Usually undocumented, the children are denied the right to education and healthcare. Now advocates are appealing to the South Korean and Chinese governments and seeking the cooperation of the United Nations and the international community to help North Korean mothers get access to their children again.

Few of these women have shared their stories in public, out of fear and shame. But some have come together to form a group called Tongil Moms (“tongil” is the Korean word for “unification”) to ask for help in their quest.

Last week, three members of the Tongil Moms advocacy group participated in a forum on human trafficking in China at the Heritage Foundation in Washington, D.C. Three North Korean women who are now South Korean citizens ­– sometimes referred to as “defectors” – spoke about their experiences in order that China respect their right as parents.

“The participants have changed multiple times because they could not face the trauma of having to retell their stories,” said Kim Jeong-ah, executive director of Tongil Moms, who was joined by two other members, Hwang Hyun-jeong and Lee Young-hee. “Naturally, women only share their stories with friends they are very close with and trust. This is because women defectors feel shameful about their experiences. It is extremely difficult for me when I share what I have been through. I was sold for 19,000 Chinese yuan [about $2,800]. Moreover, I have to confess the fact that I abandoned my child, whether it was against my will or not.”

According to South Korea’s Ministry of Unification, around 30,000 North Koreans have resettled in South Korea, the vast majority of them women. Assessing how many of them were victims of human trafficking is difficult, as is estimating the number of North Korean women who remain trafficked in China or are imprisoned back in North Korea after forced repatriation. Kim estimates 60 percent of North Korean women in South Korea were abused in China.

It is the Chinese government’s policy of forced repatriation of North Korean refugees that leads to mothers having to abandon their children, says Kim. Under international law, China is prohibited from sending North Korean refugees home, where they face torture and other reprisals. Instead, China is obliged to offer them protection under several international treaties, including the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) and the Convention Against Torture, as well as customary international law which prohibits forced repatriation (also called refoulement). Officially, however, the Chinese government says that North Koreans who flee the country are not genuine refugees but illegal immigrants coming to China for economic reasons.

“Because of the constant threat of being forcibly repatriated to North Korea, I was never able to sleep for more than one hour at a time; I would lay awake every night,” said Kim.

The Committee on the Rights of the Child (CRC) urged China in October 2013 to “cease the arrest and repatriation of citizens of the Democratic People’s Republic of Korea [North Korea], especially children, and women who have children with Chinese men, and ensure that children of mothers from the Democratic People’s Republic of Korea have access to fundamental rights, including the right to identity and education.” The CRC made similar recommendations in previous years, as have many other U.N. committees and human rights bodies.

“The last time I spoke with my daughter in 2013, she said, ‘Mom, you’ve left me, haven’t you? You hate me, don’t you?’ When a child says that, her mother will be devastated, don’t you think?” said Kim. “The daughter I have not seen since she was five years old repeated this to me endlessly. It seemed like my world was collapsing around me.”

The Tongil Moms are making three demands. They want children born to North Korean mothers and Chinese fathers to be given proper identity documents that would entitle them to education and healthcare. According to the Commission of Inquiry on Human Rights in the Democratic People’s Republic of Korea, some 20,000 to 30,000 children born to North Korean mothers in China are believed to be stateless. The group also wants mothers to have access to their children along with other parental rights. And it wants the children to be given the choice to reunite with their mothers.

“If we continue to ignore these problems, it will continue to be a huge obstacle for these women to adjust to South Korean society. They will pretend as if nothing happened or hide what happened. They will look ‘normal’ during the day, but will then cry at home alone, sobbing because they miss their children in China. However, it is different when their suffering is shared with other people,” said Kim.

“If I do not share my story, I will be in pain and cannot hold my head up in front of my child one day. I could say nothing if my child asked me what kind of efforts I made in order to find her.”

This story was reported with the help of Rosa Park, director of programs and editor of the Committee for Human Rights in North Korea, who conducted the interview with Kim Jeong-ah in Korean and provided translation.

A version of this article originally appeared on the HRNK Insider blog.