A Russian An-24 aircraft carrying 49 people, including five children and six crew members, crashed in the mountainous Amur region on Thursday, killing all on board, according to local media reports.

The ill-fated flight, operated by the Siberia-based Angara Airlines, had departed from Blagoveshchensk and was en route to Tynda, near the Russia-China border, when it lost contact with air traffic controllers shortly before its scheduled landing.

According to Russia's state news agency TASS, the aircraft reportedly caught fire mid-air and vanished from radar.

Rescue helicopters later located the burning wreckage on a remote mountainside, approximately 16 kilometres from Tynda.

Officials from the Amur Centre for Civil Defence and Fire Safety confirmed that "no survivors were found when a Mi-8 search helicopter flew over the crash site."

"The aircraft caught fire upon crashing," said a spokesperson. "Rescue operations have been hampered by the extremely difficult terrain, as the crash site lies on a steep, inaccessible slope."

The harsh geographical conditions of the region -- dense taiga forests and swampy terrain -- further complicated rescue efforts.

The aircraft did not send any distress signals before disappearing, heightening questions over what went wrong.

Preliminary reports suggest the An-24 may have been attempting a second approach to land at Tynda Airport when it went off the radar.

A Rosaviatsia aircraft and multiple rescue teams were immediately dispatched to the area when the information was received earlier in the day.

"All necessary forces and means have been deployed to search for the plane," said Amur region governor Vasily Orlov.

Investigators from the Far Eastern Transport Prosecutor's Office have launched a probe into the incident.

The cause of the crash remains unclear, and officials are expected to begin recovery operations and black box retrieval once ground access becomes possible.