A twin-turboprop Antonov An-24 passenger aircraft with 47 aboard, five of them children, disappeared on Thursday on a flight over Russia’s Far Eastern Amur Region, state media said. The plane lost radio contact with air traffic control just before it was to land.

The aircraft was flying from Blagoveshchensk to Tynda, a distance of about 570 kilometers, when it vanished from radar screens. Amur Region Governor Vasily Orlov confirmed that the manifest had 43 passengers and four crewmen. Emergency officials said communication was lost when the plane was only a few kilometers away from Tynda Airport.

There is an extensive search and rescue mission instigated immediately. Authorities are, however, having great difficulty due to the thick taiga, a huge boreal forest that encompasses most of the Amur region and makes both air and ground investigations very difficult.

Amur regional governor Vasily Orlov reported on Telegram that initial information was that there were 43 passengers, five children, and six crew members on the flight for a total of 49. “All required forces and means have been sent to search for the plane,” wrote Orlov. The emergencies ministry reported a slightly different number, saying there were about 40 people on board the aircraft.

The Antonov An-24, which was pioneered in the 1950s under the Soviet regime, is a sturdy airplane widely used throughout Russia for both cargo and passenger flights, with more than 1,000 examples manufactured.

Through early evening in Moscow, there are no reported sightings of wreckage or survivors. Authorities continue to explore the conditions under which the plane vanished.