Police officers stand guard outside Kaohsiung Prison, southern Taiwan, February 11, 2015. Six armed inmates have taken the warden and officials as hostages at the prison. [Photo/Agencies]

TAIPEI - A justice official says six armed inmates who held a warden and a head guard hostage at a prison in southern Taiwan have committed suicide after releasing the hostages.

Taiwan's administrative deputy chief of justice Chen Ming-tang said during a television interview that the hostage takers shot themselves in the early morning Thursday.

The justice authorities said the inmates were serving long sentences for burglary, murder and drug crimes and took four rifles, six handguns and more than 200 bullets from the prison's armory. They had been demanding safe exit from the prison in the port city of Kaohsiung.

Authorities did not offer any video or other evidence Thursday morning of the reported suicides, but a news conference about the standoff is under way.

Within hours, armed police had surrounded the prison. Authorities also had called on relatives of the inmates to plea for the release of the hostages, but the two sides remained in a standoff more than six hours after the inmates rebelled.

Authorities said they turned down the inmates' demands that the police force be withdrawn and that two fully fueled vehicles be provided to allow the felons to leave in exchange for the safety of the detainees.

The confrontation leader, Cheng Li-te, belongs to the notorious mafia-type organization Bamboo Union and is serving a 28-year sentence for homicide. The other five inmates are serving sentences ranging from 25 years to life.

The inmates used the need for medical care as a pretense to lure prison guards before kidnapping them, the central news agency said.

The United Daily News said it got on the phone with Cheng, who said the act had been long planned and that he was prepared to die for it. The newspaper said Cheng complained about the tendency of judges to presume guilt, insufficient allowances for inmates and unfairness in granting medical paroles.

Authorities said deputy warden Lai Chen-jung and head guard Wang Shih-tsang volunteered to swap with the two guards who were initially taken hostage. Later, Chen, the prison warden, offered to exchange with Lai as a hostage.