A passenger plane crashed in Russia’s far east on Thursday, killing all 48 persons on board, AP reported.

The An-24 aircraft, operated by the Siberia-based Angara Airlines, dropped off radar screens while approaching its destination of Tynda, a remote town in the Amur region bordering China, The Guardian quoted Russia’s local emergencies ministry as saying.

It had initially departed from Khabarovsk, then continued to Blagoveshchensk, before heading onward to Tynda, AP reported.

Parts of the burning wreckage were discovered 15 kms from the airport in Tynda on a mountainside, The Guardian quoted unidentified authorities as saying.

Footage being circulated by the Russian media showed thick smoke rising above a dense forest at the location reported to be the crash site.

Yuliya Petina, an emergency services official, said that an “Mi-8 helicopter belonging to Rosaviatsiya [Russia’s Federal Agency for Air Transport] discovered the fuselage of the aircraft, which was on fire,” during the search operation, the news agency reported.

“The An-24 plane was flying along the Khabarovsk-Blagoveshchensk-Tynda route,” The Guardian quoted emergency services as having told Russian news agencies. “It failed to pass security checks near its final destination. There is no contact with it.”

The cause of the crash remains unclear. Russia’s Interfax news agency quoted unidentified emergency service officials as saying that adverse weather conditions could have been a reason, AP reported.

An investigation has been announced into the crash. The Russian transport investigative committee has said that malfunction and human error were also being considered as causes of the crash.

The An-24 is an aircraft designed by the Soviet Union’s Antonov Design Bureau in the 1950s.