A fire caused by faulty electrical equipment killed 13 boys at an Islamic school in Myanmar on Tuesday, the fire service said, although some Muslims voiced concern since it followed a wave of anti-Muslim violence in the Buddhist-majority country.

The boys suffocated after the fire broke out in a dormitory of the school in the central, multi-ethnic Botataung district of the former capital of Yangon at about 2:40 am.

Yangon Region Fire Service said it was setting up a team to investigate the fire with the police, the electricity company and representatives of Muslim groups.

"The fire, caused by the overheating of the transformer placed under the staircase, spread, trapping the boys sleeping in the attic. As a result, 13 twelve-year-old boys died of suffocation after inhaling smoke," a fire service officer said, reading from a statement.

About 70 boys were thought to have been sleeping in the dormitory, which is in a mosque compound. Most managed to escape when fire officers broke open the double-locked doors to the building, Colonel Win Naing, chief of Yangon Division police, told reporters.

He said a case had been opened that could lead to action for negligent homicide being taken against those responsible for the mosque. An imam, or religious teacher, was taken in for police questioning on Tuesday, said an official at a mosque where the surviving children were being housed.

Neighbours and witnesses said the doors to the dormitory may have been locked due to security concerns after violence elsewhere in the country in March, and the windows were barred.

Riot police cordoned off the area but a crowd that gathered was peaceful.

Electrical faults are major causes of fires in Yangon.

But, against the background of the recent sectarian violence, many Muslims were "very suspicious" about the latest fire, said Mya Aye, a Muslim member of the 88 Generation Students' pro-democracy group.

"We are worried and sad because innocent children died," he said.

At least 5,000 people attended a funeral service for the victims in the afternoon at a Yangon cemetery, Reuters reporters said.

"The school just reopened yesterday and now my son is dead," wept Ohnmar Lwin as she buried her child.

Yangon, by far the biggest city in Myanmar, escaped the recent anti-Muslim violence although authorities posted police outside mosques and ordered restaurants in some areas to close early on some evenings as a precaution.

Officially, 43 people died in the Buddhist-led violence, which erupted in Meikhtila town in the centre of the country on March 20 and included the fire-bombing of mosques.

It spread to at least 15 other towns and villages until President Thein Sein ordered soldiers and police to crack down. – Reuters