A 29-year-old man was arrested on Tuesday morning for allegedly threatening Prime Minister Srettha Thavisin's life in a posting on the X platform, formerly Twitter.
Krisada Panbanphaeo was taken into custody at his house in Soi Suan Luang in Bangkok's Chom Thong district.
According to police, on Sunday Mr Krisada posted a picture of the prime minister on the X platform along with rude messages calling for the death of the "tall" man in the picture, and offering a reward.
When police arrested him, the suspect allegedly admitted to having posted the photo and messages and explained that he was disappointed his favourite political party had not carried through with its election promises. He apologised and said he was ready to face the consequences.
Police charged him with making threats against another person, under Section 392 of the Criminal Code. The offence carries a maximum penalty of a month in prison and/or fine of 10,000 baht.
On Tuesday Mr Srettha, who heads the Pheu Thai-led government, said he was aware of the case and authorities had taken appropriate action.
The government was open to criticism but would rather it be constructive, not threatening, he said