TAIPEI (Taiwan News) — A letter bomb exploded at a Xinwu District post office in Taoyuan at 7:56 a.m. on Wednesday (Nov. 17), setting the docking area ablaze and filling the air with smoke.

Postal workers sprang into action, raising the alarm and calling in firefighters, who extinguished the inferno within about half an hour, according to a UDN report.

Taipower cut the power to the location so wires in electrical boxes would not melt. The post office has closed for the day while investigations are carried out.

One postal worker recalls the moments leading up to the big boom, saying they first heard a rattling sound within one of the packets. This was followed by a sudden bang and smoke emanating in all directions.

Alerted by the smoke, the worker turned their head to see a fireball erupting, with flames soaring toward the roof.

Nearby residents described seeing streams of smoke reaching up many tens of meters into the sky. A loud noise that sounded like a car wheel deflating filled the air, they said.

Nine fire trucks and two ambulances were sent to the site of the blast. No one sustained serious injuries.

The parcels that the letter bomb was hidden among contained sweet potatoes, bottled tea, and other seemingly harmless items. It is not known how long the investigations will last.