MOSCOW, July 22 (RIA Novosti) - Six out of eight people on board a Mi-8 helicopter that crashed in southern Russia on Wednesday morning have died, a Russian air navigation service source said.

The helicopter, belonging to energy giant Gazprom, left Volgograd at 8:02 a.m. Moscow time and contact was lost two hours later.

"Preliminary reports said six out of eight people on board have died," the source said. "The helicopter was flying over a pipeline."

The two survivors - the crew captain and second pilot - have been hospitalized in a nearby town, the source added.

The Interstate Aviation Committee (IAC) confirmed the crash, but did not give any details, adding only that an air accident commission had taken off for the crash site.