Rio de Janeiro's police and firefighters declared a strike Friday, just a week before Carnival kicks off, raising fears of violence and crime as tourists arrive for the famed parades and street parties. Firefighters and the civil and military police announced the strike in a joint protest in downtown Rio, saying they would keep a third of their forces on the job, according to the state-run Agencia Brasil. But hours later, the commanding officers of the military police published a short statement saying all of their units were functioning normally. "There isn't any stoppage of any service for citizens," the statement said. It wasn't clear whether that meant members of military police rank and file were striking. Nearly 300 police officers and firefighters were disciplined by state officials for participating in the strike, Agencia Brasil reported, including 11 people accused of urging or inciting the action. The police union announced it would hold a demonstration to show support for those arrested or disciplined, according to a statement on the union's website. Salvador -- Brazil's third largest city and a popular destination for Carnival -- was hit by a wave of killings and looting when its police launched a strike last week. The military helped quell the violence there, and more than 14,000 troops were on standby to move into Rio if necessary, according to Agencia Brasil. Police and firefighters are demanding wage increases. Rio attracts hundreds of thousands of tourists to its lavish pre-Lenten Carnival celebration every year, and this year has an even higher profile because the country is gearing up for the soccer World Cup in 2014. The police strikes have heightened concerns over the country's ability to provide adequate security. Both Rio and Salvador are going to host games, and Rio is going to host the Olympic Games two years later.