SINGAPORE - Serangoon residents were startled by blasts that sounded like explosions on Friday night (May 5).

The sounds occurred about two minutes apart, shortly before 11pm.

One resident, 45-year-old purchaser Ms Zhu Mei Zhen, told Chinese daily Lianhe Wanbao that she thought someone had fallen from a height when she heard the first noise at about 10.45pm.

Ms Zhu said she saw two youths, who appeared to be teenagers, place a box near the rubbish chute of Block 413 Serangoon Central, just across the road from Nex Mall.

The box later "exploded", causing the second bang.

Police later cordoned off the area around the rubbish chute. No injuries or damage to property were reported.

The Singapore Police Force on Saturday said they were alerted to a case of "intentional alarm" at 10.50pm on Friday night (May 5) and that they were looking into the matter.

The Singapore Civil Defence Force said that the incident was a "false alarm", as no explosion had occurred.

Last month (Apr) two MRT stations were shut down due to security scares. On April 2 the Hougang station was closed for 20 minutes after staff found an unattended bag left behind by a 39-year-old man, who was later arrested, while he ran an errand.

And a "suspicious substance" - later found to be baking flour, left by a running group to mark a route - was found in Woodleigh station on Apr 18, leading to a three-hour closure.

One member of the group was arrested, while another two assisted in investigations.