After a raid in the southern Brazilian city of Araçatuba, bank robbers lashed hostages to the tops of their getaway vehicles.
At least three people were slain, according to police, including one suspect.
More than 50 persons were involved in the theft, according to officials, who blocked highways with burning automobiles and planted explosive devices throughout the city.
In recent years, large-scale bank robberies have become increasingly common, with hostages being exploited as human shields.
The mayor of Araçatuba, Dilador Borges, claimed police had struggled to interfere.
He told Band TV that “the cops can’t go on the attack, they can’t face them because there are too many lives on the line.”
He said he did not know if the robbers had freed the hostages yet but said the security forces had retaken control of the city centre.
Schools will remain closed on Monday and the mayor urged people to stay indoors, warning them of the danger of the explosive devices.