An explosion at a firework factory in central Thailand killed at least 20 people on Wednesday, a rescue worker said.
The exact death toll was not immediately clear but around 15 to 17 people are estimated to have been killed, according to Kritsada Manee-In, a rescue worker with the Samerkun Suphan Buri Rescue Foundation.
The blast, whose cause has yet to be determined, took place in a rural area in Suphan Buri province, about 120km north of the capital Bangkok.
Thai prime minister Srettha Thavisin, who is currently at the World Economic Forum in Davos, Switzerland, was briefed by phone call and called for a swift investigation.
The incident occurred less than a month before Chinese New Year in February, when demand for fireworks is strong.
In July last year, a large explosion at a fireworks warehouse in southern Thailand killed at least 10 people and wounded more than 100.