Colombo, Jun 29 (IANS): The Sri Lankan military Friday prepared to launch an operation to rescue three prison guards taken hostage by inmates of a prison in the north of the country, Xinhua reported.

The three guards at the Vavuniya prison were taken hostage Thursday evening by Tamil Tiger suspects. Overnight negotiations to secure their release had failed, an official said.

The area surrounding the prison had been cordoned off.

The rebels held at the prison were angered over moves to transfer some of the prisoners to another detention center in Sri Lanka's south, a region dominated by the majority Sinhalese community.

Three prisoners were transferred to the Boosa detention center in the southern town of Galle following a court order.

The hostage takers demanded that the three inmates be returned to Vavuniya immediately in order to set the prison guards free.

The Vavuniya prison has in the past had tensed situations caused by Tamil Tiger suspects jailed during and after the ethnic conflict.

Some of the Tamil Tiger prisoners have not yet faced court charges and the government has decided to open new courts to expedite their cases.