Indonesian authorities were investigating the cause of a fire that ripped through a karaoke bar in the country's third-biggest city of Medan killing 20 people, police said on Saturday.
The fire on Friday evening started on the third floor of the nightclub and spread rapidly, with most of the victims suffocating due to thick smoke, police and media reports said.
The bodies of 20 victims had been identified and two people were in a critical condition out of 13 hospitalised after the fire in the provincial capital of North Sumatra.
"We're still uncertain on the cause of the fire," North Sumatra police chief Badrodin Haiti said by telephone.
He said police were questioning employees and witnesses.
Indonesia, the world's fourth most populous country, frequently suffers natural and man made disasters and buildings are sometimes badly maintained and safety rules not properly enforced.
