The attack on the Erawan Shrine in central Bangkok on Monday evening killed 20 people and injured scores.
Police are searching for three suspects.
An arrest warrant has been issued for one unidentified man seen on CCTV footage leaving a backpack at the shrine shortly before the blast.
The Hindu shrine is popular with Buddhist, and Chinese tourists, but the spokesman said authorities did not believe Chinese people had been the "direct target" of the attack.
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