All 62 people aboard a passenger jet flying from Dubai to southern Russia were killed when their plane crashed on its second attempt to land at Rostov-on-Don airport, Russian officials say.
Russia's emergencies ministry said the aircraft, a Boeing 737-800 operated by Dubai-based budget carrier Flydubai, crashed at early on Saturday (local time) and most of those aboard were Russian.
"The aircraft hit the ground and broke into pieces," the Investigative Committee of Russia said in a statement on its website. "There were 55 passengers aboard and seven crew members. They all died."
Both of the plane's flight recorders have been recovered undamaged, the committee said in a statement.
According to the independent US-based Flight Safety Foundation, there was strong wind at the airport with a speed of 43km/h, with gusts up to 69km, but visibility was reasonable.
"Different versions of what happened are being looked into, including crew error, a technical failure and bad weather conditions," the committee said.
Flydubai's CEO Ghaith al-Ghaith told a news conference in the Gulf Arab emirate that it was "too early" to determine the cause of the crash.
"We will have information about the circumstances of the incident and the black box in the future, and an investigation is being conducted in cooperation with the Russian authorities and we are waiting to see the results," Ghaith said.
Sergei Melnichenko, head of Aviation Safety consultancy in Moscow, said so far nothing pointed to an act of terrorism.
"But nothing can be fully ruled out until a complete decryption of the flight recorders is done."
The plane was in a mid-air holding pattern for more than two hours, the Russian investigative committee said. The crash occurred more than two hours after the plane, flight number FZ981, was scheduled to land.
The Flydubai airline had a clean safety record before the accident. It started flying in June 2009, with a fleet of new Boeing 737s, one of the world's most widely flown planes.
The Flydubai plane came down inside the airport's perimeter, about 250 metres short of the start of the runway.
The plane's wing hit the ground on its second attempt to land and burst into flames, the Rostov region's emergency ministry said in a statement. But Russian news agencies cited a source in the emergency services saying that the plane fell vertically and hit the ground with its nose.
Both the pilot and co-pilot had over 5000 hours of flight experience each.
The pilot was Cypriot, the co-pilot Spanish.
Flydubai said in a statement there were 44 Russians among the 55 passengers, eight Ukrainians, two Indians and one Uzbek. Four children were among the dead.
Russian President Vladimir Putin ordered assistance to be given to the relatives of those killed.