Brazil's federal government will shortly send a national security force of military policemen to Rio de Janeiro state, apparently to curb gang violence before Carnival in February.
Drug gangs opened fire on police stations and set fire to buses last week in attacks that have killed 19 people and hurt tourism in Rio, Brazil's second-largest city.
Sergio Cabral, Rio de Janeiro's governor, requested federal troop assistance to keep violence from marring the five-day event when tourists flood the city to enjoy samba parades.
Sao Paulo state suffered a similar wave of attacks in May that left nearly 200 people dead, including 40 policemen.
Terrorism
Luiz Inacio Lula da Silva, the Brazilian president, has called the attacks "terrorism that must be dealt with by the strong hand of the Brazilian state".
Cabral said on the state government's website that, "the president is worried, because the barbarities in Sao Paulo and Rio ... show that we have to toughen our criminal legislation".
Luiz Fernando Correa, the national security secretary, and Jose Mariano Beltrame, Rio de Janeiro's state security secretary, met on Wednesday to weigh options on how to crack down on gangs.
Some 7,700 national security officers have been deployed on three occasions since they were created in 2004, though neither in Rio, nor Sao Paulo.
Security problem
Clovis Bergagao, a political analyst in Brazil, said that security is a problem that affects every part of Brazilian society.
"The problem with violence is ongoing because there is a lack of collaboration with the state and the federal government and the corruption that is inside the police."
Rio is one of the most violent cities in the world, with an annual murder rate of 50 per 100,000 people.
Authorities are particularly concerned about security as Rio is due to hold a Mercosur trade bloc summit and the 2007 Pan American Games.