The governor of the Brazilian state of Rio de Janeiro has requested the deployment of a national security force in a bid to curb soaring gang violence.
The move follows a wave of deadly violence in the state in December
The move follows a wave of gang attacks on buses and police stations there in December which left 19 people dead.
Governor Sergio Cabral said military police would arrive soon. He has also asked for federal troops.
The authorities are under great pressure to improve public safety in the run-up to next month's Carnival.
The new measures were announced after a meeting between Mr Cabral and the country's senior security official, Luiz Fernando Correa, as well as representatives of the armed forces.
Mr Cabral, who took office on 1 January, said that it was time for joint action against the violence.
"Once the public authority organises itself, no criminal can win," he said.
Police officers and stations have been targeted
He did not give details of the number of personnel expected, but said that their first duty would be to patrol the state borders in an attempt to stop the movement of drugs, arms and gang members.
The national security force, which consists of 7,700 personnel, has been deployed three times since it was created by Brazilian President Luiz Ignacio Lula da Silva in 2004.
In addition, some of the large numbers of soldiers, sailors and air force personnel permanently based in Rio will be ordered out of their barracks to supplement the police presence.
Mr Cabral also announced he would be meeting the governors of the other states in the populous south-east of Brazil next week to put into effect a new regional security programme in an effort to clamp down on urban gang violence.
It remains to be seen what practical impact these measures will have, says the BBC's Tim Hirsch in Sao Paulo, but officials know they have to improve public security not only ahead of the Rio Carnival but for the Pan-American Games due to take place in Rio in July.
In his inauguration address on Monday, President Lula condemned the recent violence in the state.
"This barbarity that happened in Rio de Janeiro can't be treated like common crime, it's terrorism, and must to be dealt with by the strong hand of the Brazilian state," he said.
In one incident, seven passengers were burnt to death when gunmen torched their bus. At least 12 police stations and posts in different parts of Rio were attacked with grenades and automatic fire.
Rio is reputed to be one of the most violent cities in the world.
Its shantytowns are frequently the scene of shoot-outs between officers and gang members, as are poor neighbourhoods in other Brazilian cities.
In May a similar wave of gang violence occurred in Sao Paulo, but the state governor, Claudio Lembo, turned down the offer of federal help.