In the early 20th century, an internationally publicized controversy arose over charges that Angolan contract workers were being subjected to forced labour and unsatisfactory working conditions. Sporadic labor unrest and dissatisfaction continued well into the 20th century, culminating in an outbreak of riots in 1953 in which several hundred African laborers were killed in a clash with their Portuguese rulers. The anniversary of this "Batepá Massacre" remains officially observed by the government.