"Today we reached the crash site... and we found 12 victims and they were all dead. We will continue the evacuation process," said National Search and Rescue Agency head Daryatmo.
"I still don't know the condition of the bodies, but we haven't been able to evacuate them. The bodies are still in body bags," he told reporters in Jakarta.
He said that rescuers arrived at the crash site in Mount Salak by helicopter and foot.
The rescue operation crew used ropes to climb the mountain, said authorities.
According to the authorities, the helicopters which tried to reach the crash site were forced to return owing to thick fog, that hampered their operations.
Russian Sukhoi Superjet 100 went missing on Wednesday near Mt. Salak in West Java. All passengers onboard were reported dead.
The passengers onboard included several Russian Embassy diplomats, journalists and representatives from airline companies.