SINGAPORE - Several loud sounds were reported in various locations across the island, including Orchard and Bukit Timah, at about 11.30am on Saturday (April 27).

Police said later at 10pm that the sounds could be related to planned detonation activities carried out by the Singapore Armed Forces at the Southern Islands that started at 11.45am and ended at 1.30pm.

This was after the police verified the matter with the Ministry of Defence.

Police also advised members of the public not to be alarmed.

Earlier in a statement on their Facebook page at about 1.30pm, the police said that they were in the midst of determining the cause of the sounds.

In an update at 2.15pm, the police said that they did not find anything incriminating or abnormal after they carried out checks on the ground.

The police added there were no injuries reported.

Reader Jessica Choo-Tan told The Straits Times that she heard two "explosion-like" sounds and felt some vibration just before 11.30am in Owen Road in the Novena area.

The 40-year-old housewife added that her friend who lives next to Novena MRT station had also heard the sounds and felt the vibration.

"But other than the sounds, I didn't spot anything unusual," she said.

Later at about 12pm, she heard another loud sound.

A 48-year-old lawyer, who gave her name as Nicole, told ST that she "felt the house shake" around noon. She lives in the Newton area.

"My sliding windows were rattling in their frame and at first, I thought there was some construction work going on," she said, adding that she did not hear any loud sounds.

She said her neighbours also shared that they had experienced the vibrations, but did not hear anything.

There was also a second shake about half an hour later, though "it was less violent than the first", she added. "It's quite worrying."

In response to the police's Facebook post, several users said in the comments that they noticed the sounds in other areas as well, including Hougang, Lim Chu Kang, Aljunied, Queenstown, Bugis and Woodlands.

Some Facebook users added that they thought it was the sound of thunder.

User Trina Liu said: "I thought it was thunder and felt the ground shake a little."

Earlier this month, on April 12, several people living in the eastern part of Singapore took to social media to report that they heard a loud sound and some tremors in the wee hours of the morning.

A Reddit user who lives in Loyang said his windows shook for a few seconds.

Other users of the online discussion platform reported hearing a loud boom.

These were later attributed to effects from an explosion at a Petronas oil and gas facility in Pengerang, Johor.

Two men were injured in the fire and explosion at the Pengerang Integrated Complex, which happened at 1.25am.

Emergency and fire response teams were deployed and the fire contained within 30 minutes.

Bernama reported that the situation returned to normal by 6.30am, with no trace of smoke left visible.