An organization that supervises foreign trainees coming to Japan to learn technical skills attempted to pressure a 25-year-old man from the Philippines to leave his labor union, the union said Sunday.

The man arrived in Japan in April 2015 and began working at a construction firm in Saitama Prefecture, north of Tokyo, with three others. They were subjected to regular physical and verbal abuse from their superiors, leading them to join the Kanagawa City Union in December 2016.

The labor union sent a request to AHM Cooperation, the body overseeing the group's time in Japan under the country's Technical Intern Training Program, to find them a new workplace.

But last April, AHM faxed the labor union a letter asking that the four withdraw from the union because the immigration bureau and the government-backed Japan International Training Cooperation Organization had advised that no companies would be willing to accept foreign interns who are unionized.

The labor union contends it is a violation of the trainees' constitutional rights and has asked a prefectural labor relations committee to step in.

Officials at both AHM and JITCO declined to comment because the case was being examined by the committee. The Tokyo Regional Immigration Bureau also declined to comment on the case but said generally speaking the bureau does not advise that trainees leave their labor unions.