BANGKOK - Three people were killed and 39 others were injured in a bomb explosion at an annual festival in Thailand's Tak province, authorities said on Saturday.

In a social media post, Prime Minister Paetongtarn Shinawatra expressed her deepest condolences to the families of the deceased and the injured in the explosion that occurred shortly before midnight on Friday.

Paetongtarn ordered the police and security agencies to swiftly investigate the incident, apprehend the perpetrators and bring them to justice, as well as instruct authorities to enhance security measures at all upcoming festivals to ensure public safety.