Two American siblings trapped in China are making a public plea for help. Cynthia and Victor Liu traveled to the country last year to pay respects to their dying grandmother but have not been allowed to return home to the U.S. because of a so-called "exit ban."

Their estranged father, Liu Changming, is one of China's most wanted fugitives. Liu, who fled the country in 2007, is the former executive of a state-owned bank and is linked to a $1.4 billion fraud case. Their lawyer says the Chinese government is using them to convince their father to return to China even though Cynthia and Victor insist they have no way of contacting him. The Trump administration's National Security Council spokesman told CBS News that Chinese authorities have given no legitimate explanation for refusing to allow Cynthia and Victor Liu to return to the U.S.

In a video you'll see only on "CBS This Morning," Cynthia Liu describes the terrifying ordeal that began nearly a year ago.

"We've done nothing wrong, and we need to go home," Cynthia said. "We wake up every morning terrified."

Cynthia, 27, works for a New York consulting firm and Victor, a 19-year-old Georgetown undergrad, are desperate to return home to the U.S. But their lawyer David Pressman said Chinese authorities won't let them leave the country.

"Each time when they present themselves at the border, they are taken to a room, and then they are ultimately told that they are not allowed to leave," Pressman told CBS News' Margaret Brennan. "Victor barely understands the language. I mean, it's bewildering, it's difficult, it's stressful."

The siblings are stuck in China under what is known as an "exit ban," a tactic used by Beijing that allows foreigners to move around the country but prevents them from leaving it. State Department warned Americans about China's exit bans in January. Even though the Liu siblings are not accused of wrongdoing, the bans can last days or years.

"We feel trapped. We live with constant distress because this is not our home, and we are not here by choice," Cynthia said in the video.



Cynthia and Victor's lawyer said the Chinese government is using them as a form of "human bait." Cynthia insists she is powerless.

"This man abandoned my family many years ago," she said. "We are not in touch with him, nor do we have any way of contacting him."



In recent years, Chinese President Xi Jinping has led a heavy-handed crackdown on corruption, and family members of the accused are often treated as if they were tied to the illegal acts. It is just one of China's many human rights violations documented by the State Department. And balancing concern about those against Beijing's heavy economic influence is getting increasingly difficult.

National Security Adviser John Bolton's call last year to release the Lius went unheeded. They now hope their plight will be raised with top Chinese officials in Washington this week for trade talks.

"I have told Victor again and again that no matter how dark our lives can be, we need to hold on to hope," Cynthia said.

Adding to their distress, the children have not been able to see or speak with their mother Sandra, a U.S. citizen who is imprisoned in China. It's unclear why she is in prison.

The siblings are not under house arrest and are free to move anywhere within China, according to their lawyer, though he said Chinese security services monitor their movements.

China's government has not responded to CBS News' request for comment.