Updated with hostage release.Russian authorities on Sunday said they brought a swift end to a siege at a detention center in the southern Rostov region, killing Islamic State hostage-takers and freeing two prison guard captives.The prison service had said earlier that two guards had been taken hostage by an unspecified number of Islamic State detainees, adding that negotiations for the release of the captives were underway.But a short time later it issued a statement saying the siege had ended."During a special operation...

the criminals were liquidated and the employees who were taken hostage were released and were not injured," the prisoner service said.No further details were released in the immediate aftermath of the drama at Detention Centre 1 in the Rostov region's capital city.A police source told state news agency TASS that IS members who were due to appear in court on terrorism charges were among the hostage-takers.They were reported to be holed up in the prison courtyard, armed with a pocket knife, a baton and an axe, the source said.The Interfax news agency said there were six hostage-takers who demanded to be provided with a car and be allowed to leave the prison in exchange for the release of the hostages.The incident comes nearly three months after gunmen killed at least 144 people when they opened fire inside a concert hall near Moscow in an attack claimed by the Islamic State.More than 20 people have since been arrested in connection with that attack, including the four suspected gunmen.Russia has been repeatedly targeted by attacks claimed by IS militants, though the militant group's influence in the country remains limited.