Seven passengers were killed and one was injured when a bus exploded in Myanmar's main city Yangon early on Monday morning, a police official said.
The blast occurred at 2:30 am (Sunday 2000 GMT) as the bus headed north through the city, said the police official who did not wish to be named.
The official said the explosion had been caused by a faulty re-fitting of the bus to run on cheaper natural gas instead of petrol, a common practice in impoverished Myanmar.
Myanmar has also been hit by a spate of bombings which authorities have mostly blamed on armed exile groups, but when a bus explosion at a busy Yangon intersection last month and injured three passengers, officials did not say whether it was caused by a bomb.
State-run media has also begun blaming blasts on democracy activists, accusing two members of detained opposition leader Aung San Suu Kyi's National League for Democracy (NLD) of bombing pro-government offices in July.
The NLD won a landslide victory in elections in 1990, but the junta never allowed it to take office and Nobel peace laureate Aung San Suu Kyi has been under house arrest almost continuously since.
The military has ruled Myanmar since 1962, partly justifying its grip on power by claiming the need to fend off ethnic rebellions.