Goa, Daman and Diu remained an outstanding issue. On 15 August 1955, five thousand non-violent demonstrators marched against the Portuguese at the border, and were met with gunfire, killing 22. In December 1960, the United Nations General Assembly rejected Portugal's contention that its overseas possessions were provinces, and formally listed them as "non-self-governing territories". Although Nehru continued to favour a negotiated solution, the Portuguese suppression of a revolt in Angola in 1961 radicalised Indian public opinion, and increased the pressure on the Government of India to take military action. African leaders, too, put pressure on Nehru to take action in Goa, which they argued would save Africa from further horrors. On 18 December 1961, following the collapse of an American attempt to find a negotiated solution, the Indian Army entered Portuguese India and defeated the Portuguese garrisons there. The Portuguese took the matter to the Security Council but a resolution calling on India to withdraw its troops immediately was defeated by the USSR's veto. Portugal surrendered on 19 December. This take-over ended the last of the European colonies in India. Goa was incorporated into India as a centrally administered union territory and, in 1987, became a state.