Update:
The explosion occured at about 10am at the Army Ordnance Department near Saphan Daeng Bridge in Bang Sue district of Bangkok and injured five personnel.
Army spokesman Winthai Suvari said the explosion happened while technicians were disassembling an RPG launcher in which a grenade had failed to launch and remained stuck inside .
They were in a maintenance tunnel for safety reasons.
The five technicians suffered head wounds and chest injuries and were rushed to Phramongkutklao Hospital, where they were reported to be out of danger, the spokesman said.
"This accident happened inside a military unit and there was no impact outside it," Col Winthai said.
The injured were identified as Banjerd Chiangsai, Bancha Sriprayoon, Kantapol Pakcharoen, Santiparp Kerdnoi and Teerapat Sriniyom.
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