
Deputy police spokesman MajGeneral Suraphol Thuanthong suggested the bomb was designed to cause disruption while discrediting the police and government. He did not link the bomb to antigovernment rallies.
Initial reports said TNT was placed at a police box near Wissukam Bridge located near the Pracha Kasem Intersection, a few kilometres from Government House, where People's Alliance for Democracy demonstrations continue.
The blast broke windows of nearby buildings and destroyed plant pots near the police box.
MajGeneral Khattiya Sawasdiphol, an Army officer who reached the scene quickly, said TNT was placed underneath an airconŽditioner compressor outside the box. It was probably detonated remotely, he said.
Suraphol said later police analysis predicted disruptions such as this within a threetosevenday period.
PAD leaders denied responsibility. Chamlong Srimuang said the bomb was designed to "paint a bad public image of the PAD".
Chamlong said the PAD rally had continued for 100 days without violence or incident. "The first bomb was set off just a few days after the progovernment movement began mobilising," he added.
Somsak Kosaiyasuk, another group leader, said the bomb was meant to scare away people wanting to join the antigovernment movement.