RIO DE JANEIRO: Twenty-six inmates were killed in eruptions of violence inside two prisons in northern Brazil, officials said Sunday as they quelled the latest in a string of jail disturbances across the country in which more than 100 people died within two weeks.

The state security office for Rio Grande do Norte state had reported earlier in the day that there were 27 deaths, but later lowered that by one. It also said all bodies had now been counted.

State security officials said fighting between rival gangs broke out Saturday at the adjacent Alcacuz and Rogerio Coutinho prisons near the city of Natal.

Officials waited until dawn Sunday before entering to try to re-impose control, state security chief Caio Cesar Bezerra said.

"This way we guaranteed a calm intervention, a pacific intervention without resistance from the inmates," Bezerra said.

Brazilian President Michel Temer expressed concern over the rebellion through his official Twitter account, saying Sunday that he was following the situation closely.

Like many prisons across the country, Alcacuz is overcrowded, with more than 1,000 inmates crammed into a facility meant for 620.

The recent outbreak of prison violence began on January 1-2, when 56 inmates were killed in the northern state of Amazonas. Authorities said the Family of the North gang targeted members of Brazil's most powerful criminal gang, First Command, in a clash over control of drug-trafficking routes in northern states. Many of the dead were beheaded and dismembered. Four other inmates were killed at a smaller prison.

Then on January 6, in the neighboring state of Roraima, 33 prisoners were killed, many with their hearts and intestines ripped out.

Experts say First Command is exploiting overcrowding and squalid conditions in the penitentiaries to expand its reach across the national prison system.

Meanwhile, the prison chief for the southern state of Parana, Luiz Alberto Cartaxo, told Brazil's Globonews network that 21 inmates escaped from the Piraquara prison on Sunday after using explosives to break through the prison wall. He said two other inmates died in a confrontation with police while trying to flee.