YANGON: A fire killed 13 students at a Muslim school in Myanmar's main city on Tuesday, police said, raising tensions in the wake of sectarian clashes despite police assurances that the blaze was accidental.

The government called for calm and sent security forces to the scene after an angry crowd gathered demanding answers about the deadly fire in Yangon, which follows a wave of Buddhist-Muslim killings and arson in central Myanmar.

“Thirteen people, mostly children, were killed during a fire at a Muslim religious school in downtown Yangon,” a police officer at the scene told AFP.

“We assume that it was due to an electrical short circuit.” The doors to the building — which housed a mosque and a religious school where dozens of children were staying in a dormitory — were apparently locked, according to government spokesman Ye Htut, preventing the students from escaping until emergency services arrived.

Police promised to establish a committee — including Muslim leaders — to look into the cause, while the government urged people to avoid spreading rumours.

“Please don't believe some news on the Internet portraying this case as a religious conflict,” Ye Htut posted on his Facebook page.

Safety standards are generally poor in impoverished Myanmar, which is emerging from decades of military rule.

Some Muslim leaders, however, voiced suspicions that the fire was started deliberately because students and teachers said they had slipped on an oily liquid on the ground floor while escaping.

“The oil smelled like petrol or diesel,” said Shine Win, a Muslim leader, urging the government to “reveal the truth”.

One student who escaped told AFP that his legs and clothes were dirty with the oily liquid.

“I slipped when I stepped on something like oil and almost fell down. As the fire was so big at that time, I didn't recognise what it was,” he said.

Scorch marks scarred the outside of the building, according to an AFP reporter at the scene, as three military trucks carrying soldiers arrived to keep the peace.

Communal tensions are running high in the former army-ruled country after at least 43 people died last month in a wave of sectarian violence that saw mosques and homes burned down in several towns in central Myanmar.

The government has imposed emergency rule and curfews in some areas.

Yangon has been tense but mostly peaceful following the clashes, which were apparently triggered by an argument in a gold shop in the town of Meiktila that triggered a riot that later spread.

The conflict poses a major challenge for President Thein Sein, who has won international praise for his reform efforts since taking office two years ago.

The situation has calmed in recent days after the former general on Thursday vowed a tough response over the violence, which he blamed on “political opportunists and religious extremists”.

Sectarian strife involving Buddhists and Muslims in the western state of Rakhine last year left at least 180 people dead.