Chun Sakada, VOA Khmer Original report from Phnom Penh Vietnamese National Assembly Chairman Nguyen Phu Trong arrived in Cambodia Wednesday for a four-day visit, as rights groups attacked the treatment of minority monks and others in the Mekong Delta region. Twelve separate organizations advocating for the rights of the Khmer Kampuchea Krom ethnic group issued a three-page statement criticizing Vietnam’s treatment of the group ahead of the visit. The organizations accused the Vietnamese government of persecuting the monks, including the defrocking of 16. Three monks recently disappeared in Vietnam, the groups said. The treatment of the ethnic group is a highly politicized, potentially volatile issue in Cambodia. Nguyen Phu Trong was scheduled to meet with his counterpart, Heng Samrin, as well as Senate President Chea Sim, Prime Minister Hun Sen and King Norodom Sihamoni. Sam Rainsy Party lawmaker Keo Remy followed the groups’ call for Vietnam to improve its treatment of Khmer Kampuchea Krom monks and others. “When Vietnamese authorities put pressure on the Khmer Kampuchea Krom,” he said, “it will affect the state of mind of central Khmers (in Cambodia) and Khmers living abroad.” National Assembly President Heng Samrin said the treatment of the monks and other minority group members was an internal affair of Vietnam, in which Cambodia cannot interfere.