 Back in Lisbon , the ' Armed Revolutionary Action ' branch of the Portuguese Communist Party , which was created in the late 1960s , and the Revolutionary Brigades ( <unk> ) , a left @-@ wing organisation , worked to resist the colonial wars . They had carried out multiple <unk> and bombings against military targets , such as the attack on the <unk> air base that destroyed several helicopters on March 8 , 1971 , and the attack on the NATO headquarters at <unk> in October of the same year . The attack on the Portuguese ship Niassa illustrated the role of the colonial wars in this unrest . Niassa ( named after a Mozambican province ) was preparing to leave Lisbon with troops to be deployed in Guinea . By the time of the Carnation Revolution , 100 @,@ 000 draft <unk> had been recorded . 
