BANGKOK >> An explosion at a fireworks factory in central Thailand killed about 20 people on Wednesday, according to provincial officials, though the devastation at the scene has made the death toll uncertain.

The information office of the Suphan Buri provincial government initially announced that 23 people had been killed in the mid-afternoon blast, but on Wednesday night revised its figure to 19 dead and three missing. The national Department of Disaster Prevention and Mitigation’s earlier preliminary figure had been least 20 people killed.

Suphan Buri is about 95 kilometers (60 miles) northwest of Bangkok, in the heart of Thailand’s central rice-growing region.

Photos posted on social media showed a thick plume of black smoke over the scene. Photos posted online by local rescue workers showed the factory site virtually leveled.

The office of Prime Minister Srettha Thavisin, who is in Switzerland for the World Economic Forum, distributed a video showing him being told over the phone by the regional police commander that there were 20 to 30 workers at the factory at the time of the explosion and that none of them could be found.

Rescue workers at the scene said there were no survivors. None were mentioned by provincial authorities, contradicting the disaster department’s statement that wounded people had been found.

Kritsada Manee-In, a rescue worker with the Samerkun Suphan Buri Rescue Foundation, who earlier estimated that around 15 to 17 people had been killed, said an exact count was difficult because the bodies were in pieces.

The Lunar New Year is celebrated in February, when demand for fireworks is strong in Thailand and other parts of Asia. The national disaster agency said the cause of the explosion is under investigation.

National police chief Torsak Sukvimol confirmed local news reports that there had been another explosion at the factory in November 2022 that killed one worker and seriously injured three others. He said police would pursue legal action for any wrongdoing involved in the new blast.

In July last year, a large explosion at a fireworks warehouse in southern Thailand killed at least 10 people and wounded more than 100, according to officials.

That explosion in Narathiwat province was in a residential area and damaged about 100 houses within a 500-meter (1,640-foot) radius, according to the Department of Disaster Prevention and Mitigation.

The Narathiwat governor said that blast was likely ignited by construction work in the warehouse, with sparks from metal welding causing the fireworks stored inside to catch fire and explode.