Rio De Janeiro , Brazil ( CNN ) -- Fourteen people died and another 25 were arrested Wednesday in drug-gang violence in Rio de Janeiro , Brazil , military police said Wednesday . That brings the total to 22 dead and 153 arrested since Sunday , police said . The gangs have shot up a police station and torched at least five buses and 11 cars in the attacks , officials said . It was not immediately clear if all the dead were gang members , or if civilians and police also suffered fatalities . The violence stems from the transfer of prisoners from local institutions to federal lockups in other states , the government-run Agencia Brasil news outlet reported , citing Rio de Janeiro Public Security Secretary Jose Mariano Beltrame . Some of those prisoners ordered the violence , Beltrame said . The attacks also came as a result of police trying to remove some drug gang members from Rio 's slums , called favelas . Beltrame said two rival gangs joined forces to launch the attacks . The security chief also said he mobilized all police in the city to try to restore order and to step up police presence in 17 of Rio 's slums . Brazilian President Luiz Inacio Lula da Silva addressed the situation Tuesday . `` I called the justice minister and told him to attend to Rio de Janeiro with whatever he needs , '' Lula told CNN affiliate TV Record . Officials are concerned about crime in Brazil as the nation prepares to host the 2014 World Cup soccer tournament and the 2016 Summer Olympics , which will be held in Rio . Journalist Luciani Gomes contributed to this story .
Brazil : 153 suspects have been arrested since Sunday , police say . The attack was triggered by the release of prisoners , security official says . Two rival drug gangs collaborated to launch the attacks , he says . The attacks started simultaneously in Rio de Janeiro .