A Thai rescue member walks at the scene of an explosion at a firework factory in Suphan Buri on Thursday. AP

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. Provincial authorities, contradicting the disaster department’s statement that wounded people had been found, mentioned none.

Associated Press