RIO DE JANEIRO — Violent clashes among rival drug factions in several prisons in the northern Brazilian state of Amazonas have killed at least 55 people, corrections officials said on Monday.

The outbreak of violence, which began on Sunday, is the latest in a state where drug gangs have waged a vicious battle for supremacy as smuggling routes that run along northern Brazil have become increasingly profitable.

The bloodshed comes as the Brazilian government is taking steps to assert greater control of the country’s chronically overcrowded and underfunded prisons, where drug kingpins have long managed to run their trade from behind bars with relative ease.