A group of immigrants who were detained in a Colorado facility while awaiting deportation proceedings are suing the private prison contractor, claiming they were paid $1 per day to do janitorial work and even threatened with solitary confinement for refusing to work, the Associated Press reported.

The immigrants, detained at a suburban Denver facility, allege that Florida-based detention contractor GEO Group Inc. coerced them into performing various tasks, including scrubbing toilets, mopping and sweeping floors, laundry and preparing and serving meals.

GEO is one of the largest providers of correctional facilities to the federal government, as it is often used for the detention of suspected illegal immigrants or legal permanent immigrants who face deportation due to their criminal records, according to the company's website.

Immigrants facing deportation occupy some 34,000 beds in private and government-run facilities nationwide, with more than 60 percent being in private facilities, Anita Sinha, a faculty member of and immigrant labor researcher at American University, told AP.

GEO said in court documents that the work immigrants do is voluntary and claims that the $1-a-day pay is in accordance with federal guidelines.

The company attempted to have the lawsuit dismissed, but U.S. District Court Judge John L. Kane declined that request on Monday, according to AP.

Attorneys for the immigrants said they have heard for years that it is common for immigrants to perform labor for next to nothing, and they indicated that they plan to seek out additional complainants and file a class-action suit. The attorneys said this is a first-of-its-kind suit.