Investigators at the scene of a small bomb which exploded Wednesday on Bangkok's Ratchadamnoen Avenue.

BANGKOK — A small bomb struck Ratchadamnoen Avenue in Bangkok’s old quarter Wednesday night, wounding two street cleaners.

Police said the pair was emptying their trash bin in front of the former office of government lottery agency when the explosives went off at about 8pm.

Police described the injuries as minor. They said the explosives were likely ping-pong bombs detonated by low-yield gunpowder.

The bomb struck on the eve of Thailand’s enactment of the new constitution and a public holiday marking the 235th anniversary of the Chakri Dynasty’s reign.

Related stories:

New Charter to be Promulgated on Thursday