By Saphora Smith

LONDON — The organs of members of marginalized groups detained in Chinese prison camps are being forcefully harvested — sometimes when patients are still alive, an international tribunal sitting in London has concluded.

Some of the more than 1.5 million detainees in Chinese prison camps are being killed for their organs to serve a booming transplant trade that is worth some $1 billion a year, concluded the China Tribunal, an independent body tasked with investigating organ harvesting from prisoners of conscience in the authoritarian state.

“Forced organ harvesting has been committed for years throughout China on a significant scale,” the tribunal concluded in its final judgment Monday. The practice is “of unmatched wickedness — on a death for death basis — with the killings by mass crimes committed in the last century,” it added.

In 2014, state media reported that China would phase out the practice of taking organs from executed prisoners and said it would rely instead on a national organ donation system.

The Chinese Ministry of Foreign Affairs on Tuesday was not immediately available to comment on the tribunal’s findings.

In a statement released alongside the final judgment, the tribunal said many of those affected were practitioners of Falun Gong, a spiritual discipline that China banned in the 1990s and has called an “evil cult.” The tribunal added that it was possible that Uighur Muslims — an ethnic minority who are currently being detained in vast numbers in western China — were also being targeted.

The tribunal is chaired by Sir Geoffrey Nice, who worked as a prosecutor at the international tribunal for crimes committed in the former Yugoslavia.