Prisoners have taken hostages in a remote prison colony in Russia’s southwestern Volgograd region, authorities say.
Federal prison authorities said “there are casualties” as a result of the hostage-taking in the IK-19 Surovikino facility, about 120 km (74.5 miles) west of regional centre Volgograd, without specifying numbers.
State news agency Tass said one person had been killed and four people taken to hospital with injuries.
An unverified image posted on social media appeared to show an inmate holding a knife standing above a bloodied prison guard.
Separately, an unverified video showed a man apparently brandishing a knife, standing in a prison courtyard.
Emergency services said three prisoners were involved in the hostage-taking. It was unclear how many hostages had been taken.
Authorities said they were preparing to free the hostages.
Volgograd region Governor Andrei Bocharov said the hostage-taking posed “no threat to the civilian population”.
The Kremlin said President Vladimir Putin had been briefed on the situation.
The Volgograd hostage-taking is the second such incident this summer, after six prisoners who pledged allegiance to the Islamic State group captured two guards at a facility in the neighbouring Rostov region.
Five prisoners were killed and a sixth sentenced to 20 years in prison following the attack.
Prosecutors said they had opened a case relating to a hostage taking.
IK-19 Surovikino is a high-security penal colony. It is believed to hold about 1,200 inmates.
