"The plane has been seen by rescuers from air on the slope of Mount Salak, but we still have not arrived at the spot yet," Gagah Prakoso, spokesperson of the National Search and Rescue Agency, told Xinhua by phone.
The spokesperson could not give further detail about the condition of the plane.
The Russian Sukhoi Superjet-100 on a demonstration flight over Indonesia went missing Wednesday.
Indonesian transport ministry spokesman Bambang Ervan had said that the plane took off from Indonesian air base Halim Perdana Kusuma in East Jakarta.
It lost contact at 2.25 p.m. while trying to descend from 10,000 feet to 6,000 feet near a small airport in Bogor.
The SSJ-100 carried out two demonstration flights in the Indonesian capital.
It arrived in Jakarta as part of a demonstration tour of six Asian countries. It has been to Myanmar, Pakistan and Kazakhstan and was due to visit Laos and Vietnam.
The Superjet 100 is a medium-haul passenger aircraft developed by Sukhoi in cooperation with US and European aviation corporations, including Boeing, Snecma, Thales, Messier Dowty, Liebherr Aerospace and Honeywell.