Tourists walk along Nathan Road in Mongkok, one of the busiest and most popular commercial areas in Hong Kong. Photo by Shutterstock 13 Vietnamese nationals, nine men and four women, will spend 15-20 months each in prison for working illegally in Hong Kong. Hong Kong police arrested the Vietnamese citizens, aged 21-56, in Tsuen Wan District for illegally working in food factories, restaurants, residential apartments and cleaning companies. The arrests were made on March 27 as part of a campaign against illegal workers, Asia Times reported. They failed to show valid personal identification documents and were found using forged Hong Kong identity cards, the report said. Three employers suspected of hiring the illegal workers were also detained and the investigation is still ongoing, it added. Hong Kong is one of the top destinations for Vietnamese workers looking for jobs overseas, and reports of illegal Vietnamese workers being arrested have appeared frequently in recent years. Vietnam sent a record 140,000 workers abroad last year, an increase of 7 percent from a year ago. According to the International Organization for Migration, around 100,000 Vietnamese leave the country every year for more developed destinations.