RIO DE JANEIRO - Forced evictions of slum dwellers to make way for the 2016 Olympic Games show that human rights could suffer during Brazil's preparations for the event, the head of Amnesty International said on Monday.

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Among other projects, Rio de Janeiro plans to build three expressways for buses ahead of 2016 that will pass through several slums, or favelas, that are home to thousands of residents. Despite Brazil's economic rise, millions of slum-dwellers still live a precarious existence in major cities.

"Our worry is that because of the Olympics now this thing could get scaled up very significantly," Salil Shetty, Amnesty's secretary general, said in an interview as he started a weeklong visit to the South American giant.

Authorities in recent months have begun demolitions in some slums, offering compensation for houses or new housing that residents complain is often on the distant outskirts of the city, far from their workplaces and communities.

While the number of evictions has so far been small, Shetty said that the initial signs of how Rio is treating residents in the path of infrastructure projects have not been good.

"Everybody fully understands that some degree of movement might be inevitable when you're undergoing such a major project, but the issue is whether the fair process is being followed," he said.

"These people have been given houses which are 50 km (31 miles) away from their livelihood, or compensations which are really a pittance. The communities are not really involved."

Shetty was due to meet residents of the affected communities and said he would raise the issue with government officials, possibly including President Dilma Rousseff, in the capital Brasilia later this week.