Inmates kill prison guards at Russia prison, hold hostages

Snipers from Russia's National Guard on Friday killed four inmates who had stabbed four prison guards to death and briefly held others as hostages, while declaring allegiance to the Islamic State group , officials said.

The Federal Prison Service said that four inmates took eight prison guards and four inmates hostage. It said they stabbed four of the guards, three of whom died on the spot and the fourth one later died at a hospital. The agency said three other guards were hospitalized with injuries.

Russia's National Guard said its snipers "neutralized" all four attackers, freeing all the hostages, while the Federal Prison Service also claimed credit for killing the assailants. The discrepancy couldn't be immediately explained.

Details of the violence at the IK-19 prison colony in Surovkino in the Volgograd region, 535 miles southeast of Moscow, were sparse and it was not clear how the inmates had taken hostages several hours earlier.

While the incident was unfolding, Russian President Vladimir Putin said the "situation" would be discussed at a regular meeting of the country's Security Council.

Videos that purportedly came from the scene and circulated on Russian media and messaging app channels showed men wielding knives inside and in a prison yard and several men in what appeared to be guard uniforms lying in blood on the ground.

In the videos, the alleged attackers claimed support for the Islamic State group and for the suspects arrested in the March terrorist attack on a Moscow concert hall that left 145 people dead. An ISIS affiliate claimed responsibility for that attack, in which gunmen killed patrons waiting for a popular music group to perform and set the building on fire.

At the time, a U.S. official told CBS News the U.S. provided intelligence to Russia about a potential attack under the intelligence community's Duty to Warn requirement.

The state news agency Tass said court records showed that the hostage-takers were from former Soviet Central Asian countries; all the concert hall attack suspects are from Tajikistan.

Volgograd regional governor Andrey Bocharov alluded to reports on social media that the attackers were not Russian citizens, but did not confirm their identity.

"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.

An Islamic association -- the Spiritual Administration of Muslims of the Russian Federation -- said it "categorically rejected" the "atrocity" and claimed it was "inspired from outside Russia."

It is the second incident of prisoners with apparent ISIS connections taking hostages, following a similar siege at a jail in the southern Rostov region in June.

Russian special forces then killed most of the hostage-takers, detained one, and freed the guards.

ISIS has repeatedly pledged to target Russia over its support of Syrian leader Bashar al-Assad , who has waged a military campaign to quash the group in the Middle East.

AFP contributed to this report.