At least three people have been killed and 48 others injured after an explosive device was thrown into a crowd at a festival in northern Thailand, authorities said.

The attack occurred just before midnight on Friday at the annual Red Cross Doi Loyfa fair in the Umphang district of Tak province, near the border with Myanmar.

Among the injured, six people are in critical condition, according to local police. Two suspects have been detained for questioning, though no charges have been filed yet, the Associated Press and local media reported.

Police responded to the scene at approximately 11:30 p.m. local time (4:30 p.m. GMT). Witnesses said the explosive landed near the foot of an outdoor stage where attendees were dancing.

Several reports suggest the device was an improvised explosive device (IED). Images from the aftermath show debris scattered across the festival grounds, which were illuminated by string lights.

Prime Minister Paetongtarn Shinawatra expressed condolences to the victims’ families and vowed a thorough investigation. In a statement posted on X (formerly Twitter), she said, “I have directed security agencies to investigate the explosion and ensure all necessary assistance for the affected families.”

The prime minister also instructed police to increase security measures at festival venues across the country.

The Umphang rescue team confirmed that some of the injured had been transported to a nearby hospital for treatment.

The Red Cross Doi Loyfa fair is a week-long event that attracts between 8,000 and 9,000 attendees each year. The attack occurred on the penultimate night of this year’s celebration, held in the southernmost district of Tak province.

Umphang borders Myanmar to the west, a region that has seen periodic unrest, though the motive behind the attack remains unclear.

The incident marks a rare occurrence of violence at such community events, prompting heightened concerns over public safety in the region.