MOSCOW/DUBAI (Reuters) – 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 on Saturday, Russian officials said.

Russia’s emergencies ministry said the aircraft, a Boeing 737-800 operated by Dubai-based budget carrier Flydubai, crashed at 3:40 a.m. Most of those on board 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 U.S.-based Flight Safety Foundation, there was strong wind at the airport with a speed of 43 kilometers per hour, with gusts up to 69 kilometers, 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.

It said the plane was in a mid-air holding pattern for more than two hours. The crash occurred more than two hours after the plane, flight number FZ981, was scheduled to land.

Russia’s Interfax news agency cited a source in the emergency services as saying the pilot changed his mind about landing on the approach to the airport.

“For an unknown reason, several minutes before the landing, the pilot reconsidered and decided to make another circuit, but wasn’t able to,” Interfax quoted the source as saying.

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.

ALERT

Security officials in the Middle East are on heightened alert for militant threats to aviation following the Islamic State claim of responsibility for downing a Russian passenger plane over Egypt’s Sinai Peninsula in late October, in which all 224 people on board died.

Sergei Melnichenko, head of Aviation Safety consultancy in Moscow, said so far little pointed to an act of terrorism.

“Nothing points to that,” Melnichenko said. “But nothing can be fully ruled out until a complete decryption of the flight recorders is done.”

According to the flight tracker Flightradar24, an Aeroflot flight SU1166 from Moscow made three landing attempts in Rostov before being diverted. It landed at 11:15 p.m. in Russia’s Krasnodar.

A source familiar with the investigation told Reuters that there was no weather-related ban on landing at the airport. “We consider all possible causes, but no one is even talking now about the possibility of a terrorist attack,” the source, who spoke on condition of anonymity, said.

Dubai’s civil aviation authority said it was sending an investigative team to Russia, president Ismail al Hosani told reporters.

Under international aviation rules, the investigation will be led by Russia’s air crash safety investigation agency with representatives from the United States, where the jet was made and the United Arab Emirates where the airline is based.

Boeing will be appointed as technical advisers to the U.S. investigation team.

INTERNATIONAL CREW, MOSTLY RUSSIAN PASSENGERS

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.

It suffered an incident when one of its planes was shot at while landing at Baghdad airport on Jan. 27, 2015.

The aircraft that crashed was just over five years old.

The Flydubai plane came down inside the airport’s perimeter, about 250 meters 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 on its nose.

Grainy pictures from a security camera pointing towards the airport, which were broadcast on Russian television, showed a large explosion at ground level, with flames and sparks leaping high into the air.

Ghaith of Flydubai said that he had no information to indicate that the pilot had issued a distress call. Both the pilot and co-pilot had over 5,000 hours of flight experience each, he said.

There was one Russian among the seven-person crew, the Russian emergency ministry said in a statement. The pilot was Cypriot, the co-pilot and another crew member Spanish and the other three were from Seychelles, Colombia and Kyrgyzstan.

Flydubai said in a statement that there were 44 Russians among the 55 passengers, eight Ukrainians, two Indians and one Uzbek. Four children were among the dead.

Russian agencies cited Rostov’s government representative as saying that the remains of those killed had been taken to a local morgue and families would able to identify them on Sunday.

Russian President Vladimir Putin ordered assistance to be given to the relatives of those killed.

“The head of state said that now the main thing is to work with the families and the loved ones of those who had died,” the Kremlin said in a statement on its website.

(Additional reporting by Noah Browning, Christian Lowe, Tim Hepher, Sam Wilkin, Ali Abdelaty, Jason Bush and Gleb Stolyarov; Writing by Lidia Kelly and Noah Browning; Editing by Tom Heneghan and Ros Russell)