The region Pol Pot and the others moved to inhabited by tribal minorities, the Khmer Loeu, whose rough treatment (including resettlement and forced assimilation) at the hands of the central government made them willing recruits for a guerrilla struggle. In 1965 Pol Pot made a visit of several months duration to North Vietnam and China. He probably received some training in China, which must have enhanced his prestige when he returned to the WPK's liberated areas. Despite friendly relations between Sihanouk and the Chinese, the latter kept Pol Pot's visit a secret from Sihanouk. In September 1966, the party changed its name in secret to the Kampuchean (or Khmer) Communist Party (KCP). The change in the name of the party was a closely guarded secret. Lower ranking members of the party and even the Vietnamese were not told of it and neither was the membership until many years later.