MOSCOW - All six people on board an ageing Antonov An-26 transport plane that crashed in the Russian far east the previous day are thought to have been killed, Russian news agencies reported on Thursday, citing emergency services sources.

The plane, which the TASS news agency said belonged to a company that performed technical checks at Russian airports and was 42 years old, disappeared from radar screens on Wednesday. 

The emergency services ministry said on Thursday it had discovered the wreckage in hard-to-access terrain and was sending a rescue team over land.

It said the crew's fate remained unknown, but the TASS and Interfax news agencies cited an emergency services source as saying that preliminary searches suggested that nobody had survived.

Russian aviation safety standards have improved in recent years but accidents, especially involving ageing planes in far-flung regions, are not uncommon. In July, all 28 people on board an Antonov An-26 twin-engine turboprop died in a crash in Kamchatka, also in the far east.

(Reporting by Anton Kolodyazhnyy; Writing by Alexander Marrow Editing by Andrew Osborn) ((alexander.marrow@thomsonreuters.com;))