All ten were crew members aboard the aircraft involved in the accident, the navy said
The bus, carrying 37 passengers, careered into a deep ravine at the Liku Lematang area in South Sumatra province just before midnight on Monday and ended up in a river, reports the BBC.
At least 120 rescue workers were deployed to help survivors and retrieve the dead.
The cause of the accident is being investigated.
According to local media, the vehicle was going to the city of Palembang located several hours away from Bengkulu city.
Pagar Alam Police chief Dolly Gumara said the police were currently "prioritising" evacuating survivors.
He also called for victims' families to identify their relatives at the hospital.
Roads around the site of the accident have been closed and police say they have issued warnings to motorists.