Human rights activists are lobbying major jewellers to stop buying gems sourced in Myanmar as a way to exert pressure on Myanmar’s military leaders by limiting profits from the country’s lucrative mining industry, AP reported.

A report by the group Global Witness released Wednesday outlines how the army is involved in gemstone mining despite a moratorium on new licenses put in place before the military seized power on Feb. 1.

Last week, luxury jeweller Harry Winston announced it would no longer buy gemstones with Burmese origins regardless of when they were imported.