Some 3,000 Brazilian soldiers and marines had been deployed in the megacity of Rio de Janeiro on Monday to protect the upcoming municipal elections from violence and gangsters' vote-rigging.

The troops would occupy neighborhoods and slums manipulated by drug gangs and militia groups.

The gangs and groups are known for handpicking their proxies as candidates and coercing local community residents to vote for them in elections.

Some candidates to the Municipal Assembly had reported that they were not allowed to campaign in certain communities and had received threats from gangs.

Twenty-eight slums would be occupied during the week before the elections scheduled on Sunday.

Rio de Janeiro state governor Sergio Cabral had welcomed the dispatch of the troops, which was deemed as a necessary measure despite the decreasing murder rates in the state capital Rio.

"I think the Armed Forces' presence to collaborate for the election and ensure people can choose their candidates is wonderfully welcomed," he said.

On Sunday, voters in the over 5,000 cities and towns across the biggest Latin American country will elect mayors and municipal councilmen.

Other towns in Rio de Janeiro state will receive security reinforcement on that day.

Over 140 towns in Brazil also had their requests approved by the Electoral Court for the temporary deployment of federal troops.