All 44 passengers and six crew members on board a Boeing 737 that crashed on landing in the Russian city of Kazan have been killed, sources at the scene have confirmed.

The UK Foreign Office has said that a Briton was among the dead. Russian media reports identified the British national as Donna Bull, 53, who was working as an educational consultant at Bellerbys College in Cambridge.

Also on board were the son of Tatarstan's president and the regional chief of the Russian intelligence agency FSB. The crash also claimed the lives of two children.

Forensic experts are working to establish the identities of all the victims. A search and rescue operation in and around the airport has ended as all 50 bodies have now been recovered.

The passenger plane is believed to have encountered difficulties while landing and exploded into a ball of fire on touching down. The jet's nose is reported to have hit the runway when the pilot was making a second landing attempt after the first one apparently failed.

"The plane touched the ground and burst into flame," said Sergei Izvolsky, spokesperson for the aviation monitoring agency Rosaviatsia.

The jet belonged to Tatarstan Airlines and was travelling from Moscow to Kazan, the capital of the oil-rich province of Tatarstan.

The authorities have launched an investigation into the cause of the crash. Apart from Boeing officials and Russian authorities, experts from the US National Transportation Safety Board are expected to take part in the investigation.

The flight recorders of the plane, which could give a clue to what went wrong, are yet to be traced.

Speculation on the cause of the crash ranges from pilot error to unfriendly weather conditions to a technical glitch.

Russian President Vladimir Putin has expressed his condolences to the relatives of the victims. A day of mourning has also been declared in Tatarstan province.

Russia Plane crash in Kazan
Wreckage at the site of a Boeing 737-500 crash at Kazan airport Reuters
Russia plane crash in Kazan
Emergency workers at the scene of a Boeing 737-500 crash at Kazan airport Reuters