A group of construction workers are suing Hong Kong-listed Imperial Pacific and two other Chinese firms alleging they were victims of a human trafficking and forced labour scheme.

The lawsuit’s seven plaintiffs are seeking punitive damages to recoup high recruitment fees and and medical costs from injuries suffered on the job including severe burns and a partially severed finger.

These workers were among thousands of Chinese labourers brought to the tiny island of Saipan, a US commonwealth, in 2016 and 2017 to build a casino report owned by Imperial Pacific.

Job agents lured them to the tropical island with the promise of high wages and a green card if they paid recruitment fees of more than US $8,000 (£6,045), according to an amended lawsuit filed Friday in a US federal court in Saipan. Many borrowed money from loan sharks at high interest rates, using their property or homes as collateral.

But upon arrival, the men were forced to work 12-hour shifts, including at times around the clock for 24 hours, and not allowed to rest. Living conditions were squalid, and supervisors “forced them to pay fines if they did not work hard enough or arrived late,” according to court documents.

One manager, after beating up some workers, even threatened to kill employees if they disobeyed him. Those who suffered injuries given safety hazards and lack of job training were never taken to the hospital, and told they’d be arrested and deported given their temporary tourist visas and lack of proper work permits.