Bolsonaro said the deployment of 300 soldiers to the state of Ceara over the next 30 days was "apt, rapid and effective" and necessary to protect the local population.

It follows a string of attacks in Ceara over past months targeting public buildings and banks that have overwhelmed police.

Most have occurred in the state capital of Fortaleza, where main streets are deserted in daytime and trash has piled up uncollected because of halted services. Other towns also have been affected.

Intelligence reports published in the Brazilian media attributed the violence to a reaction by gangs to attempts to end their control of some prisons by separating inmates by affiliation and blocking cellphone signals.

The decision to send in troops was taken by Bolsonaro's new justice minister, Sergio Moro, a former high-profile judge who oversaw Brazil's biggest corruption probe, called Car Wash.

Ceara's governor belongs to the leftwing Workers Party, which was driven into opposition by Bolsonaro's election and that of his ultraconservative allies.

Bolsonaro swept to power on promises to harshly crack down on crime and corruption, accusing the Workers Party of lax policies toward criminals.

Brazil has the third biggest prison population in the world, behind the United States and China, with nearly 730,000 inmates as of 2016. Penitentiaries are overcrowded and prey to gangs that often viciously turn on each other.