The coming of independence in Angola and Mozambique in 1975 also altered the power balance in another way. It forced South Africa and the United States to rethink their attitudes to the area, to protect their economic and political interests. Attempts were made by both countries to pressure Smith into accepting majority rule. With Kenneth Kaunda's Zambian support the nationalist groups were convinced to come together under the united front of Abel Muzorewa's United African National Council. The imprisoned nationalist leaders were released.