Jakarta – Indonesian police have ransacked a Jakarta office of an Acehnese group linked to a fatal explosion here as the military picked up an Acehnese man suspected of manufacturing weapons for a rebel movement.

Police took a computer and a telephone from the office of the Information Centre for Aceh's Referendum (SIRA) in the raid on Monday night, said Mr Faisal Saifuddin, the Jakarta-branch SIRA chairman. Mr Faisal said police raided the house at 11 pm after the group's activists had left the building.

SIRA is a student-based organisation campaigning for a referendum on self-determination in resource-rich Aceh province, where Muslim separatists are fighting for an independent state. "This is part of a plan to destroy SIRA. We have no connection to the bombing," Mr Faisal said.

A bomb exploded on Thursday afternoon in a small house for Acehnese students in a residential area of south Jakarta, killing three people, injuring two others and causing heavy damage to the house.

Police have said they were investigating whether the blast was linked to SIRA and another non-governmental group called Solidamor.

On Monday, the military arrested 46-year-old Acehnese Tengku Saleh on suspicion of manufacturing weapons for the Free Aceh (GAM) separatist group, said Lieutenant Jailana of the Wirabraja regional military command.

Three pistols and two rifles were confiscated from the house during a raid, Lt Jailana said, adding the arrested man had confessed to repairing GAM's weapons.