Russian convicts took hostages at a prison colony in the southern Volgograd region on Friday, causing four staffers to be hospitalized, according to officials.
The siege comes two months after Islamic State-affiliated detainees held guards hostage in another facility, and ethnic tensions are high following the IS-claimed Moscow music hall bombing.
“Convicts took hostage employees of the (IK-19) correctional institution. Measures are currently being taken to free the hostages. There are casualties,” Russia’s federal penitentiary service said in a statement.
Four prison staff were hospitalised due to the attack, Volgograd governor Andrey Bocharov said.
“An operational headquarters has been set up to coordinate the work on releasing the hostages. Law enforcement and security agencies are carrying out operational activities. There is no threat to the civilian population,” he added.
Russian President Vladimir Putin said the “situation” would be discussed at a regular meeting of the country’s Security Council on Friday.
Videos published on Russian social media appeared to show prison guards covered in blood after being taken hostage.
They clips also showed the hostage-takers holding flags affiliated with IS.
AFP could not verify those images.
Russia’s investigative committee said several prisoners were involved.
Governor Bocharov did not comment on the identity of the hostage takers, but alluded to reports they were not Russian citizens.
“Everyone on our territory is obliged to respect and comply with the laws of Russia. We will not allow anyone to try to incite ethnic discord,” he said in a statement published by the regional administration.
The IK-19 prison colony is located in the town of Surovikino, around 850 kilometres (530 miles) south of Moscow.
The event occurred during a meeting of the prison’s disciplinary commission, the federal penitentiary service stated.
In June, prisoners affiliated with IS attempted a similar siege at a penitentiary in the southern Rostov region.
Following a standoff, Russian special forces were able to kill the hostage takers and liberate the guards.
Tensions over migration are high in Russia following the March attack on a Moscow concert hall, which killed 145 people and was the country’s deadliest terror incident in two decades.
A Central Asian branch of IS claimed responsibility for the incident, and the four suspected gunmen, who are currently in pre-trial jail, are Tajik citizens.
Millions of individuals from Central Asia, which was once part of the Soviet Union, live in Russia, with many performing low-wage jobs to send money home to their family.
IS has regularly threatened to target Russia for its support of Syrian President Bashar al-Assad, who has undertaken a military campaign to eliminate the group in the Middle East.