A passenger plane flying from Blagoveshchensk to Tynda in Russia's far east crashed on Thursday, Russian authorities said.

None of the 48 passengers and crew on board have survived, the head of the country's Amur region said in a statement Thursday.

The burning fuselage of the Angara Airlines Antonov An-24, one of the oldest passenger planes still in operation, was found on a hillside south of its intended destination, about 15 kilometers (9 miles) from Tynda, more than 7,000 kilometers (4,350 miles) east of the capital Moscow, the Emergency Situations Ministry said.

Rescue work was initially hampered by difficult terrain and bad weather, but local authorities said they were able to reach the crash site later in the afternoon.

What do we know about the crash?

The Russian federal government said 42 passengers, including five children, and six crew were on board the plane.

An earlier statement from the regional governor, Vasily Orlov, had put the death toll at 49. The reason for the discrepancy was unclear.

In a statement, Orlov sent his condolences to the families of the crash victims, and declared three days of mourning.

The aircraft reportedly vanished from radar during its second approach to Tynda.

According to the Emergency Situations Ministry, the crew had not reported any problems prior to the crash.

Media reports suggested that rough weather might have led to misjudgements of altitude, leading to the plane brushing the tops of trees as it approached the airport.

Russian President Vladimir Putin has been notified of the crash, the Kremlin said.

There was at least one Chinese citizen on board, according to reports. 

China's President Xi Jinping has conveyed his "deep condolences" to Putin and the families of the crash victims, according to Chinese state media outlet Xinhua.

Aging aircraft

The plane, which had reportedly been inspected before takeoff without any shortcomings detected, had begun its flight in Khabarovsk before stopping over at Blagoveshchensk, authorities said. 

The Soviet-designed aircraft was nearly 50 years old, having been built in 1976, according to Russian media citing data from the aircraft's tail number.

Russia's aviation sector has faced growing problems as Western sanctions over Moscow's invasion of Ukraine affect the availability of spare parts, among other things.

Russian prosecutors have launched an investigation into the Siberia-based airline runnng the flight.

Edited by: Elizabeth Schumacher