A passenger aircraft carrying nearly 50 people vanished from radar on Thursday while flying over Russia’s remote Far Eastern region, prompting an urgent search effort, authorities confirmed. The plane, an Antonov An-24, was operated by Angara Airlines, a regional carrier based in Siberia. It reportedly lost communication with air traffic controllers as it was nearing Tynda, a small town in the Amur region, which lies close to the Chinese border.

According to Vasily Orlov, the governor of the region, initial reports suggest there were 43 passengers on board, including five children, along with six crew members.

“Search and rescue teams have been fully mobilized,” Orlov announced in a message shared on Telegram. “All available resources are being used to locate the aircraft.”

However, there appears to be some uncertainty about the total number of people on board. The local emergencies ministry provided a slightly lower estimate, saying around 40 people may have been on the flight.

As the search continues in the rugged, forested terrain of Russia’s far east, officials have yet to determine the cause of the plane’s disappearance or its current location.