The strike, for higher wages, began early Friday and follows an ongoing walkout by police in the northeastern state of Bahia. There, police stopped work on January 31, unleashing a crime wave with more than 150 homicides, looting, and vandalism mostly concentrated in the capital city of Salvador.

In Rio, the police job action is not expected to cause similar chaos because strike leaders agreed to a minimum level of service despite the protests.

However, the willingness of Brazil's police to stage walkouts when they are most needed has unsettled many and called into question the overall state of preparedness in a country with increasing first-world ambitions.

As residents went about their business on Friday in the seaside city of 6.4 million people, only a handful of precincts appeared to struggle with a shortage of officers. Still, authorities were ready with emergency plans that could deploy more than 14,000 federal troops across the city and the surrounding state of the same name.

President Dilma Rousseff last week deployed more than 4,000 troops to Salvador to try to restore order. Given a growing call for walkouts nationwide by police officers demanding higher salaries, state and federal officials prepared for similar measures in Rio.

"There is a contingency plan," said Colonel Frederico Caldas, a spokesman for the police force. "But it isn't necessary with the current situation."

The strike comes just one week before Rio's famous carnival celebrations and coincides with the start of hundreds of informal street parades, known as blocos. As many as 850,000 tourists are expected to hit the beaches and palm-tree lined promenades of Brazil's second-biggest city for the festivities, which officially start on February 17 and end on February 22.

The walkout also renews concerns that Brazil, eager to show off its growing prosperity during the World Cup two years from now, is ill-equipped to provide the security needed in the 12 cities selected as venues for the soccer games, including Rio and Salvador. Rio will also play host to the 2016 Olympics.

EXTENT OF STRIKE UNCLEAR

As the strike moves forward, it is unclear how many of Rio's security personnel will walk off or how long their strike may last.

In Bahia, roughly 6,000 officers, or about a fifth of the state's overall police force, have taken part. Out of Rio's 70,000-strong force, which also includes firemen and state prison guards, only about 3,000 assembled in the city's colonial centre late Thursday in an initial protest to launch the strike.

Though Rio's state assembly voted to raise the force's wages by 13 percent, with an additional increase next year, strikers are pushing for more.

State police, charged with day-to-day security in Brazil, earn far less than most private-sector workers and many other civil servants, too. In Rio, the pay raise would give police a minimum monthly wage of 1,816 Brazilian reais, about half what the police are demanding.

The low wages have forced many state police officers to moonlight and caused frustration for officers in areas like Brazil's violent northeast, where rising crime and drug problems have accompanied economic growth. Low pay has also made many Brazilian officers notoriously susceptible to bribes and collusion with armed gangs, drug traffickers and other criminals.

In Rio, where state officials have made inroads against gangs that controlled crime in the city's once lawless hillside slums, authorities feared a strike could undermine the "police pacification units" that helped restore order.

However, police units appeared to be operating normally on Friday and city residents said they had noticed little out of the ordinary. One of the more famous carnival blocos, known as the Cordão do Bola Preta, reversed plans to cancel its parade and said its march would proceed, local media reported.

In Salvador, striking police remained defiant. Bahia police also continued their walkout despite an easing of tensions on Thursday, when a group of more than 200 protesting officers agreed to vacate a state assembly building they had occupied since the start of the strike.

(Additional reporting by Rodrigo Viga Gaier in Rio, Sergio Queiroz in Salvador, and Eduardo Simões in São Paulo; Writing by Paulo Prada; Editing by Todd Benson)

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