Two guards were taken hostage at a detention centre in southern Russia where they worked.
After several hours, the security service stormed the facility and neutralised the hostage-takers, who were reported to be prisoners with links to the terrorist organisation IS.
The drama unfolded on Sunday at a detention centre in Rostov-na-Donu in southern Russia.
The perpetrators, reported to be six in number and armed with knives, a rubber baton, and a fire axe, had barricaded themselves in the facility's courtyard with the hostages.
Negotiations had begun when the security service stormed the building and freed the hostages in a special operation, reports AP citing state media. The country's prison authority stated in a statement that the perpetrators were "liquidated". Exactly what that means is unclear, local media report that at least some of the hostage-takers were killed, writes AP.
The perpetrators are described as IS members who were being held in detention awaiting trial on terrorism charges, writes AFP citing the state news agency Tass. They allegedly escaped from their cells by breaking out a grate. From there, they made their way to a corridor where the two guards were located. The hostage-takers reportedly demanded a car and weapons, as well as the opportunity to leave the facility, writes the independent Russian news agency Baza on the messaging service Telegram.
The facility is referred to as Detention Centre Number One in the Rostov region.