Russian special forces have rescued two prison guards and neutralized several assailants who had taken them hostage at a detention center in Rostov-on-Don.

Six detainees took the two guards hostage earlier on Sunday, prompting an operation to free them, according to reports from Russian media.

Initially, the prison service announced negotiations for the guards' release. Shortly after, they declared the situation resolved.

"The criminals were eliminated," Russia’s Federal Penitentiary Service stated, adding that a "special operation" had successfully freed the hostages unscathed.

Russian media, citing police sources, indicated that the hostage-takers were linked to the ISIL (ISIS) group.

RT reported that three of the hostage-takers had previous terrorism convictions, including charges for spreading extremist information and conspiring to blow up a Russian courthouse.

Journalists on-site reported gunfire, and multiple ambulances were seen arriving at the detention center, as shown in social media footage.

Images on social media seemed to indicate that at least two of the hostage-takers wore headbands resembling the ISIL flag, while other images depicted prisoners armed with knives.

The attackers reportedly dismantled the bars of a window in their cell and infiltrated a guard room where they captured at least two officers, according to local media reports.

Earlier, Russia’s state news agency TASS, quoting unnamed law enforcement sources, reported that the six hostage-takers were armed with a penknife, a rubber baton, and a fire axe in the center courtyard of the detention facility.

"The employees held hostage were released unharmed," the prison service later confirmed.

The Interfax news agency claimed the hostage-takers demanded a car and safe passage from the prison in exchange for the hostages' release.

The exact number of killed hostage-takers among the six was not immediately clear.

This incident follows an attack almost three months ago, where gunmen killed at least 144 people at a concert hall near Moscow — the deadliest assault on Russian soil since the Beslan massacre over a decade ago.

Hundreds more were injured in the assault.

More than 20 people, including the four suspected assailants from Tajikistan, have since been arrested. ISIL claimed responsibility for the concert hall attack.