One of the firecrackers exploded but the other was a dud in the incident, which occurred around around 4am, according to a report on television.
Soldiers stationed at the checkpoint, situated under the Thai-Belgium flyover, heard a bomb-like blast, and went to investigate. The found an unexploded firecrackers in front of the exit of the MRT Lumpini station, near the intersection with Sathorn Road.
The soldiers covered the unexploded firecracker with old tyres and called their military explosive ordnance disposal (EOD) unit to collect the device.
Traffic at the area intersection was temporarily choked to two lanes, but all four lanes were opened again around 7.30am.