The deaths of two construction workers at Manaus' new World Cup stadium could cause Brazil's builders to stage a nationwide strike.
A man collapsed following a heart attack while working around the Amazonas Convention Center, within the Arena Amazonia stadium compound.
That came on the same day that Marcleudo de Melo Ferreira, 23, fell to his death from 35 metres after a cable snapped on the same site. Work on high areas of the ground has been suspended until safety can be assured.
It is the third time somebody has died while working on the new project in Manaus, where England will kick off their World Cup campaign against Italy. Two workers were killed in November when a crane collapsed on Sao Paulo's Arena Corinthians, which will host the World Cup opener between Brazil and Croatia.
"A general strike would be ideal, to show the reality that nobody wants to see," Amazonas Construction Union president Cicero Custodio told Globoesporte.
"The government only shows the pretty part of the works and forgets who's there making them happen. This Monday we will be there, demanding our rights as workers and exposing this reality.
"The [cable] accident happened because there wasn't a safety technician on site. The Labour Ministry has to get off their chairs and audit the works, even when there are people working at night."
Families of the two men who died in Manaus on Saturday had claimed in the Brailian media that builders had to work seven days a week in order to get the stadium ready by Fifa's deadline. The incident which led to the 23-year-old man's death occurred at around 04:00 local time.
According to the stadium's website, work is 92 per cent complete as of December 2.
The Brazilian government faces a race against time to ensure infrastructure across the country is ready to support the World Cup, following delays, increased costs and nationwide unrest.
There is also the threat of protest from citizens angry about the spiralling cost of hosting the event. Millions of people took to the streets during the summer's Confederations Cup, stirred by price hikes on local transport networks.