Rescue teams discovered on Friday the crash...
The fighter had been performing a scheduled flight and was about 30 km away from the Dzemga airbase when it disappeared off the radar screens.
"The crash site has been discovered by military rescue teams near the town of Galichny, about 20 km [12.5 miles] north of Komsomolsk-on-Amur," the official said.
Rescuers are continuing the search for the pilot, he added.
The Su-27 is a Mach-2 class air-superiority aircraft designed as a direct competitor for the heavy fourth generation Western fighters, such as the F-15 Eagle.
About 450 Su-27 aircraft have been built for the Russian Air Force since 1984, and over 200 jets have been exported to other countries, including China, Indonesia, Angola and some ex-Soviet states.
Russia used Su-27s to gain airspace control over Tskhinvali, the capital city of South Ossetia, during a brief war with Georgia in August 2008.
Last year there were at least two fatal crashes involving Su-27 fighter jets.