Russia's special forces killed several men linked to the so-called "Islamic State" (IS) group who took two guards hostage at a detention center in the southern city of Rostov, Russia's Federal Penitentiary Service said Sunday.

"The criminals were eliminated," Russia's Federal Penitentiary Service said in a statement, describing how a "special operation" had taken place to free the hostages.

"The employees who were being held hostage were released. They are uninjured," the statement continued.

The siege took place Sunday at Detention Center 1 of the Rostov region, the prison service said.

The Interfax news agency said there were six hostage-takers. The men were said to have been armed with knives and other sharpened objects.

Men had demanded vehicle and freedom

The hostage-takers were allegedly able to remove the bars from their windows and enter a guard room, according to a Telegram channel cited by Reuters news agency.

The Interfax news agency reported that the prisoners had demanded a car and free passage.

Before the siege was quashed, one of the hostage-takers was shown on social media waving a knife next to one of the hostages.

The hostage-taker wore a headband with the flag used by the IS.

Russia has been targeted by IS in the past. In March, the jihadist organization claimed responsibility for an attack at a concert hall near the capital Moscow, in which 144 people died.

State news agency TASS cited a police source as saying that some of the hostage takers were due to appear in court on terrorism charges, while others were already convicted.

Russian media speculated that they could be among those convicted of plotting an attack on the Supreme Court of Karachay-Cherkessia, a Muslim-majority Russian republic in the Caucasus.

mm, dvv/ab (AFP, Reuters)