Fireworks explosion at Thai factory kills many

At least 18 people have died after an explosion at a fireworks factory in central Thailand.

"18 found dead, confirmed," a rescue worker said on Wednesday, revising his earlier estimate of 20.

It was not immediately clear what caused the incident, which took place mid-afternoon in Suphan Buri province about 120 km (74.56 miles) north of Bangkok, police said.

"We cannot tell whether all the workers were killed. The officials are entering the site to investigate. They have not found any survivors," Provincial governor, Nattapat Suwanprateep, told Reuters.

A preliminary investigation put the death toll at 20, according to a police statement, with many injured.

Prime Minister Srettha Thavisin was briefed on the explosion while at the World Economic Forum in Davos, Switzerland and urged a swift investigation.

"The prime minister ordered an inspection of the plant to see if it was operating legally and if the explosion was caused by negligence. The law must be enforced to the fullest extent because there are innocent deaths and injuries," Srettha's office said.

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, damaging about 100 houses within a radius of about 500 meters (1,640 feet), according to the Department of Disaster Prevention and Mitigation.

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