In 1961, Slovo and Abongz Mbede emerged as two of the leaders of Umkhonto we Sizwe (MK), the military wing of the ANC, formed in alliance between the ANC and the SACP. In 1963 he went into exile and lived in Britain, Angola, Mozambique and Zambia. In his capacity as chief of staff of MK he codetermined its activities, like the 1983 Church Street bombing. In 1982, Slovo's wife, Ruth First was assassinated in Maputo, Mozambique, where the couple lived in exile. In 1984, Slovo, an ANC and SACP member, was forced to leave Mozambique in terms of the Nkomati Accord between the Marxist People's Republic of Mozambique and apartheid South Africa. In 1984, he was elected general secretary of the SACP in Lusaka, Zambia, and in 1985, he became the first white member of the ANC's national executive.