RIO DE JANEIRO (AP) -- Thousands of demonstrators are gathering in downtown Rio de Janeiro for a march against legislation that officials here insist would strip the oil-producing state of much of its income from Brazil's energy sector.

The protesters are calling on President Dilma Rousseff to veto a measure that would divide oil royalties more evenly between all of Brazil's 26 states instead of favoring top oil producers like Rio and neighboring Espirito Santo.

State officials have spearheaded the campaign against the measure, which they say would deprive Rio of $1.7 billion in 2013 alone. They say that loss in revenue could endanger preparations for the 2014 World Cup and the 2016 Olympics.

Many of those attending Monday's march are public servants, bused in from outlying cities.

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