New clashes erupt at Brazil prison where 26 were killed
Inmates have thrown rocks at each other and set up barriers inside a Brazilian jail where 26 prisoners were recently killed in confrontations.
Images on local TV showed hundreds of prisoners in the yard of Alcacuz Penitentiary outside the north-east city of Natal.
Inmates appeared to be separating themselves into two groups with makeshift barriers of pieces of wood, mattresses and other material. Injured prisoners were seen being carried off.
No prison guards could be seen.
"We need help immediately," Robinson Faria, the governor of the state of Rio Grande do Norte, told CBN radio.
Mr Faria said he had asked President Michel Temer to immediately dispatch troops from the armed forces.
Beyond the prison, Mr Faria said he wanted the troops to help patrol the streets of Natal, where several buses were burned on Wednesday. Authorities said they were investigating whether the incidents were connected to the turmoil in the prison.
In a statement, the governor's office said "the security team is evaluating the situation".
Confrontations between two gangs in the prison erupted over the weekend, resulting in the 26 deaths. Many of the dead were dismembered.
Authorities said members of the Sao Paulo-based First Command, Brazil's largest criminal gang, known by the Portuguese acronym PCC, fought with local gang Crime Syndicate of Rio Grande do Norte.
On Wednesday, a heavily armed military police force entered the prison without violence. Authorities said they transferred 220 inmates to other prisons to avoid more clashes.
Brazil is experiencing a wave of prison killings from warring gangs. At least 126 people have died since the beginning of the year.
Security experts say the trigger was the break-up of a long truce last year between the PCC and Red Command, a large gang based in Rio de Janeiro.