Brazil is to send in the army in an increasingly desperate fight to tame runaway gang violence in Rio de Janeiro, following a decree signed Friday by President Michel Temer.

Army patrols are already used in Rio's favelas ruled by drug gangs, but the decree will now give the military full control of security operations in Rio state, which the president said had virtually been seized by organized crime gangs.

The army will have primacy over the state police, a situation unheard of since the country's return to democracy in 1985 after 21 years of military rule.

"I am taking these extreme measures because circumstances demand it," Temer said after signing the decree to combat a wave of gang-driven violence.

"The government will give tough and firm answers, taking all necessary measures to eradicate organized crime."

Chamber of Deputies head Rodrigo Maia -- who took part in a preparatory meeting with Temer on Thursday -- described the move to reporters on Friday as "hard and extreme".

The country has seen a wave of violence that prompted Defense Minister Raul Jungmann to declare last month that "the security system is broken."

Rio state Governor Luiz Fernando Pezao issued an apology Wednesday after the carnival in Rio was marred by violence and muggings: "We were not ready. There were mistakes in the first days and we reinforced the patrols."

Jungmann predicted a sharp response after meeting Temer late Wednesday.

"It is clear to us that the situation in Rio during the carnival was unfortunate," he said. "New measures will be announced."

Press reports said the army's mission will last until the end of Temer's term as president, December 31.

Brazil's armed forces deployed to Rio de Janeiro in July 2017 to help the badly overstretched police. Rio state has been badly hit by Brazil's recession and the slump in the oil market in the last few years, as well as massive corruption.