MOSCOW — All 48 passengers and crew onboard a passenger plane that crashed in Russia’s Far East have died, the head of the country’s Amur region said in a statement Thursday.

Russia’s Emergency Situations Ministry said earlier that it had found the burning fuselage of the Soviet-designed twin turbo prop plane on a hillside south of its planned destination in the town of Tynda, more than 7,000 kilometers (4,350 miles) east of Moscow.

The plane, which was operated by the Siberia-based Angara Airlines, had initially departed from Khabarovsk before making its way to Blagoveshchensk on the Russian-Chinese border and onwards to Tynda.

It wasn’t immediately clear what caused the crash. Russia’s Interfax news agency said there were adverse weather conditions at the time of the crash, citing unnamed sources in the emergency services. Several Russian news outlets also reported that the aircraft was almost 50 years old, citing data taken from the plane’s tail number.

Images of the reported crash site circulated by Russian state media show debris scattered among dense forest, surrounded by plumes of smoke.

Regional Gov. Vasily Orlov said rescuers struggled to reach the site due to its remote location, 15 kilometers (9 miles) south of Tynda.

The transport prosecutor’s office in the Far East said in an online statement that the plane was attempting to land for a second time when it lost contact with air traffic control and disappeared from radars.

Orlov announced three days of mourning in the Amur region to mark the disaster, which he described as a “terrible tragedy.”

A previous statement from the governor said that 49 people had been onboard the flight. The reason for the discrepancy was not immediately clear.

The authorities have launched a probe on the charge of flight safety violations that resulted in multiple deaths, a standard procedure in aviation accidents.

Aviation incidents have been frequent in Russia, especially in recent years as international sanctions have squeezed the country’s aviation sector.