By Angus MacSwan SAO PAUL0, Jan 14 (Reuters) - The first units of an elite Brazilian police force headed for Rio de Janeiro on Sunday on a mission to crack down on rampant crime that has caused daily bloodshed and challenges the authority of the state. About 400 troopers in the paramilitary National Public Security Force were deploying to Rio by air and by road, the government's Agencia Brasil said. The number will increase to about 6,000 in the lead-up to the Pan American Games, which will be held in Rio in July. State governor Sergio Cabral requested the troops after a bout of violence in December shocking even by Rio de Janeiro's standards. Assailants linked to drugs gangs attacked police posts and at least 19 people were killed, including seven civilians burned alive in a bus. The national force will initially stay out of the city, but will patrol highways and guard state borders to crack down on drug and gun smuggling. "We still don't know exactly what our mission is but whatever it is, will give a good account," Lt. Jose Luiz Goncalves, leader of a Sao Paulo-based platoon, told Agencia Estado. Violent crime, fueled partly by poverty, is a huge problem in Brazil. But crime-fighting has been hampered by disputes over whether it is a federal or a state responsibility. The national security force was set up two years ago to bolster state police forces. Drugs gangs control many of Rio's slums, and police often enter only in military style-invasions. Army troops occupied a dozen slums last March in a crime crackdown. In Brazil's business capital Sao Paulo in May, a gang called the First Command of the Capital launched attacks against police and public buildings that brought South America's largest city to a halt and killed about 200 people. Last week a report by the Washington-based Human Rights Watch said police violence, torture and extrajudicial killings were still widespread in the fight against violent crime Brazil, despite government efforts to rein them in. Meanwhile, the commander of a Rio police battalion, Lt. Col. Alexandre Siqueira de Andrade, was killed on Saturday in a shoot-out with two men who were stealing his car, police said.
