Four people have been killed and more than 20 others injured in a fire at a bar and nightclub frequented by foreign tourists on the southern Thai resort island of Phuket, according to local police.
Those who died in the fire early on Friday morning included two women and one man. Police said the bodies were too badly burnt to identify.
Hospital workers said foreigners were among the casualties in the blaze, including four French nationals who were among the injured.
Police Colonel Jirapat said the fire broke out shortly before 4am local time (21:00 GMT on Thursday) at the Tiger Disco in Phuket's popular Patong beach area.
He said the cause of the blaze was not yet known, but that authorities suspected heavy rains that led to sparks at a nearby electricity transformer may have triggered it.
Chamroen Tipayapongtada, Phuket's deputy governor, told AFP news agency: "The fire was caused by lightning which struck a transformer and the fire spread throughout the place."
The Tiger Pub was reported to be close to collapse after the fire. Rescue workers pulled the charred bodies of victims out of the wreckage on Friday.
Hospital workers in Phuket said the injured included both Thais and foreigners.
"We received more than 20 people who sustained injuries from the ... fire. Most are suffering from suffocation," one hospital employee said.
"Two are in critical condition from severe burns. One of them is a French man who suffered burns on his torso," she added.
"The four dead bodies were burnt beyond recognition. We cannot identify even their gender."
A team from the National Police Office was on its way to Phuket to try to identify the victims.
Outside the blackened remains of the Tiger Club nightclub, much of which was destroyed by the blaze, police kept back a crowd of onlookers as ambulances arrived to collect the casualties.
The blaze added to recent incidents that have tarnished the reputation of one of the country's premier tourist destinations.
Thailand is one of the world's most popular tourist destinations, attracting 19 million visitors last year to its beaches, temples and racy nightlife in the capital, Bangkok.
But robberies and scams are on the rise in some areas, and an Australian woman died in Phuket in June after being stabbed while trying to fend off a bag-snatcher.
Lax safety standards are a problem. In the worst incident in recent years, 66 people died and more than 200 were injured when a fire broke out in a club in central Bangkok as people were welcoming in the new year in the early hours of January 1, 2009.