KOTA KINABALU:Residents in the Sipitang and Beaufort districts in Sabah and Labuan were alarmed by an earth-shattering sound that lasted some 10 seconds at about 11 am today.

Jamlan Zainuddin, 44, a construction worker in Beaufort, said at first he thought it was the sound of the house he was repairing collapsing

''It was so sudden. It was like an explosion going off and the earth shook which caused us (he and his co-workers) to panic.

''We all got out of the house fearing it would collapse. My colleagues and I then contacted our families to ensure that they were safe,'' he said when contacted by Bernama.

A teacher, Aminah Siddek, 38, who lives in Sipitang, said she and her family immediately exited their house to save themselves upon feeling the floor shaking.

''Initially, we thought there was an earthquake in the area but could not find any information on it. We opened Facebook and it was full of stories of the tremors which were felt even in Labuan,'' she said.

She said there was much speculation about the incident by netizens and hoped the public would believe only information from legitimate sources.

Meanwhile, Beaufort district police chief, DSP Azmir Abdul Razak said investigations were being conducted to determine the source of the booming sound and urged residents to be calm.

In LABUAN, Bernama correspondent Jailani Hasan reported that loud booms rattled homes across the duty-free-island.

Residents in the villages of Tanjung Aru, Tanjung Kubong, Taman Mutiara, Sg Bedaun, Rancha-Rancha, Taman Lazenda, Kerupang and Patau-Patau 1 and 2 were alarmed at what was going on.

''It was the talk of the town here on Labuan after the booms, which lasted several seconds, were heard at around 11 am... it's like it came from the sky and I jumped up and said what was that. It wasn't someone knocking on the door, ' 'said Zulie Julkip, a Patau-Patau 1 resident.

Labuan's largest Whatsapp group, Kongsi-Kongsi Info Labuan was flooded with reports of the incident.

"I still wonder what it was," said Johan Goh, while various enforcement agencies confirmed they received numerous calls from people about the matter.

The Muara police station in neighbouring Brunei, when contacted, confirmed the incident but said did not receive any reports as of 1 pm.

Meanwhile, the Malaysian Maritime Enforcement Agency here mobilised its assets in Labuan waters and the border with Brunei to determine the source of the explosive sound.

Labuan police said they had yet to receive reports from oil and gas industry players about it.

The Labuan Fire and Rescue Department has also been reached for a possible explanation but there has been no feedback yet.

Sipitang police chief Champin Piuh, when contacted, confirmed that there was no explosion at the Sabah Ammonia Urea Project (SAMUR).

Brunei's National Seismic Centre (NSC), in its portal, remarked on Moderate Seismic Activity at 11:03 am, that was clearly not caused by an earthquake or natural tremors in Brunei and surrounding countries. The seismic activity had been felt at a number of locations in Brunei.

-- BERNAMA