NEW YORK (Reuters) - A former executive for the U.S. arm of a Chinese construction conglomerate went on trial Tuesday on American charges that he forced Chinese laborers to work on New York area construction sites under a form of “debt bondage.”

Assistant U.S. Attorney Craig Heeren in his opening statement in federal court in Brooklyn told jurors that Dan Zhong was “a leader of the U.S. arm of a criminal enterprise that exploited forced labor for personal gain.”

Zhong served as the president of U.S. Rilin Corp, a unit of China Rilin Construction Group, a privately held construction conglomerate headed by Zhong’s billionaire uncle, Wenliang Wang.

Heeren said the company offered workers in China jobs in the United States, but required them to pledge large sums of cash and even their family’s homes as security, which they would lose unless they performed all the work owed under the contract.

The prosecutor said the workers came to the United States on visas that allowed them to work only on Chinese diplomatic facilities, but were also forced to work on private properties in the New York area, including Zhong’s own New Jersey home.

Heeren said the workers’ passports were kept in a safe Zhong controlled. He said workers were told where they could live, to keep them away from New York’s Chinese communities where they might speak to others. He said those who tried to escape were recaptured, sometimes violently, describing one instance in which an escapee was seized and thrown in a van.

One of Zhong’s lawyers, Robert Cleary, said that all of the workers came voluntarily to the United States, where they could make up to five times as much money as they could in China.

“That was their choice,” Cleary said. “There was no debt, there was no bondage, there was no forced labor.”

Cleary said the jury would hear evidence that workers who finished their contracts and returned to China received their deposits back with interest, and that those workers were able to enjoy themselves in their spare time and even travel around the country.

According to the defense lawyer, Zhong was never involved in violence. Cleary said evidence would tie some practices claimed by the prosecutors not to Zhong but to another Rilin employee, Landong Wang, who was also charged in the case but is not in U.S. custody.

Zhong was arrested in 2016. His trial is expected to last two to three weeks.