Law enforcement officials estimate that tens of thousands of gangs are active across the United States, ranging from neighborhood street gangs to prison gangs and large organized criminal networks.

A system designed to protect state inmates has led to increased violence involving so-called ‘dropout’ gangs of prisoners who have defected from other groups. Authorities say one group, the Riders, ...

SÃO PAULO—A Brazilian gang founded in the country’s violent prisons is fast becoming one of the world’s biggest criminal organizations, reshaping global cocaine flows from South America to Europe’s ...

The Trump administration is weighing declaring Brazil’s two largest drug gangs terrorist groups, after lobbying by the sons of jailed former President Jair Bolsonaro. By Ana Ionova and Edward Wong Ana ...