JOHANNESBURG — A court in Johannesburg on Wednesday sentenced seven Chinese nationals to 20 years in prison each after convicting them of trafficking and forcing 91 undocumented Malawian nationals to work at a fabric factory in South Africa.

The defendants were found guilty on Feb. 25 of trafficking the migrants between 2017 and 2019 to a cotton fabric factory in Village Deep, an industrial area south of Johannesburg. Prosecutors said the victims were confined behind high walls and razor wire, guarded by armed personnel, and compelled to work 11-hour shifts, seven days a week, often without safety equipment or proper training.

Police raided the factory on Nov. 12, 2019 and discovered the Malawians confined under what court papers described as inhumane conditions. During the trial, victims testified they were transported in windowless trucks, not allowed to leave the compound, forbidden from bringing in outside food and barred from personal communication. They said they were forced to operate defective machines without protective gear, which led to accidents and injuries.

Court records listed the defendants as Shu-Uei Tsao, 42; Biao Ma, 50; Hui Chen, 50; Quin Li, 56; Zhou Jiaquing, 46; Junying Dai, 58; and Zhilian Zhang, 51. They were sentenced in the Gauteng South Division Court after being convicted of human trafficking and violating South African labor and immigration laws. Prosecutors had sought life sentences.

Investigators and prosecutors told the court that many of the victims had previously worked at Chinese-owned factories in Malawi and were recruited to South Africa under false pretenses. Authorities said the recruitment and transportation took place over a two-year period and that the factory was secured by high walls and razor fencing with armed guards controlling movement.

The convictions come amid heightened scrutiny of labor practices in some factories in South Africa, including those linked to foreign-owned businesses. Human trafficking and forced labor cases can involve multiple criminal and civil statutes, including those governing immigration, employment standards and human rights protections.

The sentencing marks the culmination of a case that began with the 2019 raid and developed over subsequent years of investigation and court proceedings. The courtroom verdict underscores prosecutors' contention that the defendants played central roles in the recruitment, transportation and exploitation of vulnerable workers.

No immediate statement was released by the defendants in court. The identities of the victims were not disclosed in full in court documents to protect their privacy. South African authorities have in past years partnered with international organizations and neighboring countries to identify and assist trafficking victims and to pursue traffickers through criminal prosecutions.

The convicted individuals will serve their sentences under South African law following the court’s orders on Wednesday.