The African National Congress Friday elected Nelson Mandela as its deputy president and announced it would move its headquarters to Johannesburg. Mandela's appointment came less than three weeks after he was released after 27 years in South African imprisonment. It is one of several titles he held before he was arrested and jailed for sabotage and conspiring to overthrow the white minority government. While in prison, he relinquished all leadership positions, and the post of deputy president slipped into disuse. His return to the second-highest office in the ANC came as no surprise, as the leadership had said that it wanted him to play a leading role in the formerly outlawed liberation movement as it moves toward negotiations with Pretoria. Mandela's friend and former law partner Oliver Tambo has led the ANC as acting president since 1967, and is equally respected and revered within the movement. Tambo, 72, however, suffered a stroke last year that has left him partly paralyzed. He is recuperating in a Swedish clinic. The ANC's 35-member national executive committee announced Mandela's and other appointments after two days of consultations in the Zambian capital, the home of the organization's exiled headquarters since the late 1970s. The governing body also said it would set up headquarters in Johannesburg "as soon as possible" and send a delegation to South Africa within weeks to discuss with President Frederik de Klerk obstacles to the return of its members to the country. _ Information from the New York Times was used in this report.