Following regional council elections held in late 1972 in areas under PAIGC control, which led to the formation of a constituent assembly, Vieira was appointed president of the National People's Assembly. The guerrilla war began to turn against the Portuguese as expenditure, damages and loss of human lives remained a burden for Portugal. Following the coup d'état in Portugal in 1974, the new Portuguese revolutionary government which overthrew Lisbon's Estado Novo regime began to negotiate with the PAIGC. As his brother Amílcar had been assassinated in 1973, Luís Cabral became the first president of independent Guinea-Bissau after independence was granted on 10 September 1974.