Banda Aceh – Angry residents in Indonesia's Aceh have disabled a tsunami warning system after a false alarm spread panic in a province still traumatized by the deadly 2004 Indian Ocean tsunami, an official said on Thursday.

Residents cut power to a siren on a tsunami warning tower in the Lhoknga area near the provincial capital Banda Aceh by smashing an electricity box, Syahnan Sobri, the head of the meteorology and geophysics agency in Aceh said.

A technical glitch prompted the siren to ring for about 30 minutes in Aceh Besar district on Monday, sending residents rushing out of their homes in panic.

"They cut the electricity connection but did not damage equipment," said Sobri, referring to the actual warning siren and tower.

"We are sending our technicians to the location to fix it. For the moment the warning system in Banda Aceh and Aceh Besar is still switched off," he told Reuters.

The Indian Ocean tsunami left some 170,000 people dead or missing in Aceh alone, inflicting deep psychological scars on many of the survivors.

Earthquakes, which sometimes cause tsunamis, are frequent in Indonesia, the world's fourth most populous country. Its 17,000 islands sprawl along a belt of intense volcanic and seismic activity, part of what is called the "Pacific Ring of Fire."

In the wake of the 2004 tsunami, Indonesian officials have come under pressure to bring in a network of warning systems, but many vulnerable areas in the huge developing country remain excluded.

There have also been frequent technical glitches with the systems in place.