In the late 1970s, Cuba's relations with North American states improved during the period with Mexican President Luis Echeverría, Canadian Prime Minister Pierre Trudeau, and U.S. President Jimmy Carter in power. Carter continued criticizing Cuba's human rights abuses, but adopted a respectful approach which gained Castro's attention. Considering Carter well-meaning and sincere, Castro freed certain political prisoners and allowed some Cuban exiles to visit relatives on the island, hoping that in turn Carter would abolish the economic embargo and stop CIA support for militant dissidents. Conversely, his relationship with China declined, as he accused Deng Xiaoping's Chinese government of betraying their revolutionary principles by initiating trade links with the U.S. and attacking Vietnam. In 1979, the Conference of the Non-Aligned Movement (NAM) was held in Havana, where Castro was selected as NAM president, a position he held until 1982. In his capacity as both president of the NAM and of Cuba he appeared at the United Nations General Assembly in October 1979 and gave a speech on the disparity between the world's rich and poor. His speech was greeted with much applause from other world leaders, though his standing in NAM was damaged by Cuba's refusal to condemn the Soviet intervention in Afghanistan.