Thai Prime Minister Prayut Chan-o-cha is under quarantine after contacting a businessperson who tested positive for COVID-19, government spokesman Anucha Burapachaisri said on Monday.

Prayut, who has been already fully vaccinated, was found standing close to Veerasak Pisanuwong, chairman of the Surin Chamber of Commerce, for a selfie photo during Thursday's visit to the Phuket Sandbox reopening campaign in southern Thailand's island province.

The prime minister, who has tested negative so far, is being quarantined at a private place and working from there, the government spokesman said.