Jakarta , Indonesia ( CNN ) -- Bad weather hampered recovery efforts Friday as rescue teams combed a forbidding slope of an Indonesian mountain where a Russian jetliner crashed on a demonstration flight this week . Rescuers found 12 bodies early in the day , according to Vice Marshal Daryatmo , head of the National Search and Rescue Agency , who like many Indonesians uses only one name . It will take at least two weeks to identify the victims through DNA tests , Indonesian authorities said . All 45 on board the Sukhoi Superjet 100 are feared dead . The Superjet 100 , Russia 's newest passenger plane , slammed into Mount Salak , a volcano south of Jakarta , after disappearing from radar screens Wednesday . Most of the wreckage is on a steep slope about 6,000 feet high , making it difficult to reach . The cause of the crash remained unclear . The Russian Investigative Committee said it has launched a criminal probe into possible safety violations . `` We can understand how the families are feeling right now , and we want to do this evacuation as fast as we can , but the problem is the crash site terrain is unreachable by parachute , '' Daryatmo said at a news conference Friday . Indonesian President Susilo Bambang Yudhoyono announced a joint investigation Friday after a phone call with his Russia counterpart , Vladimir Putin . `` I welcome the offer from Russian President Putin because the goal is to investigate what could have caused the plane crash , '' Yudhoyono said . The Russian Investigative Committee had said 48 people were on board the plane , including eight Russian crew members . But the Russian state-run news agency RIA Novosti said the number was 45 , citing Sukhoi Civil Aviation President Vladimir Prisyazhnyuk as saying three of the people on the passenger list did not board the flight . The plane was on a demonstration flight for Indonesian Ministry of Transportation officials and representatives of Indonesian airlines , the Russian Embassy in Jakarta said before the crash . Indonesia 's Sky Aviation signed a $ 380 million deal in 2011 to buy 12 Sukhoi Superjet 100s , and press reports said a number of Sky employees were on the plane that went down . Sukhoi employees are also among the missing . It was the first crash of a Sukhoi Superjet 100 , RIA Novosti said . The plane was on its second demonstration flight Wednesday when it lost contact with air controllers at Jakarta 's Halim Perdanakusuma Airport . The Sukhoi jet arrived in Jakarta as part of a demonstration tour of six Asian countries . It had been to Myanmar , Pakistan and Kazakhstan , and was scheduled to visit Laos and Vietnam after Indonesia , RIA Novosti said . Sukhoi manufactures military aircraft and is known especially for its fighter jets . Its civilian aircraft is narrow-bodied with a dual-class cabin that can transport 100 passengers over regional routes . It flew its maiden flight in 2008 and has had encountered problems in the past . In March , a Superjet 100 operated by Russia 's Aeroflot Airlines was forced to abandon its flight to Astrakhan , Russia , and return to Moscow because of problems with the undercarriage , according to RIA Novosti . A similar defect in another Aeroflot-operated Superjet 100 plane had to be fixed in Minsk in December . However , Russia 's state-run United Aircraft Corp. said the defect did not affect passenger safety . CNN 's Kathy Quiano in Jakarta and Alla Eshchenko in Moscow contributed to this report .
Recovery efforts are hampered by high elevation and bad weather . Rescuers have found 12 bodies so far . The Indonesian Sukhoi Superjet 12 slammed into Mount Salak , a volcano south of Russia . Jakarta launches criminal probe into possible safety violations .