A plane with six people aboard has disappeared in Russia's Far East, authorities say.
The Russian emergency ministry said the AN-26 aircraft went missing 38 kilometres from the city of Khabarovsk on Wednesday evening.
Officials have presumed that the plane disappeared over the Khekhtsir nature reserve while making a "technical" flight.
"According to preliminary data, there were 6 flight personnel on board," the ministry said in a statement.
More than 70 rescuers and a reconnaissance helicopter had deployed to the suspected crash site.
"Searches are complicated by the dark time of the day and unfavourable weather conditions," the ministry added.
The AN-26 is a medium-haul transport plane produced by Soviet manufacturer Antonov in the 1970s and 1980s and is used mainly to transport civilian cargo or soldiers and military equipment.
Accidents involving dilapidated aircraft in Russia's wild and remote Far East are still common.
In August, eight people were killed when a Mi-8 helicopter, with 16 people on board, crashed into a lake on the volcanic Kamchatka peninsula due to poor visibility.
In July, an airliner with 22 passengers and six crew members on board crashed as it was about to land in Kamchatka, leaving no survivors.