Media reports say the Embraer 190 jet crashed near the city of Aktau in Kazakhstan on Wednesday, killing 38 people, after diverting from an area of Russia that Moscow has recently defended against Ukrainian drone attacks.

Twenty-nine survivors reportedly received hospital treatment.

Azerbaijan Airlines flight J2-8243 had flown hundreds of kilometers off its scheduled route from Azerbaijan to Russia to crash on the opposite shore of the Caspian Sea, after what Russia's aviation watchdog said was an emergency that may have been caused by a bird strike. But an aviation expert suggested that cause seemed unlikely.

Officials did not immediately explain why it had crossed the sea, but the crash reportedly came after Ukrainian drone strikes this month hit the Chechnya region of southern Russia.  The nearest Russian airport on the plane's flight path was closed on Wednesday morning.

Reuters reports that Azerbaijan President Ilham Aliyev said according to information he had received, the plane changed course due to poor weather, but he added the cause of the crash was unknown and must be fully investigated.

“This is a great tragedy that has become a tremendous sorrow for the Azerbaijani people,” he said.

Sixty-two passengers and five crew were aboard.  Russian news agency Interfax says the death toll was disclosed by Kazakhstan’s Deputy Prime Minister Kanat Bozumbayev in a meeting with an Azerbaijani delegation in Aktau.

Azerbaijan Airlines said the Embraer 190 jet was flying from Baku to Grozny in southern Russia, but had been forced to make an emergency landing around 3 kilometers from Aktau in Kazakhstan.

"Preliminary: after a collision with birds, due to an emergency situation on board, its commander decided to 'go' to an alternate airfield - Aktau was chosen," Russia's aviation watchdog said on Telegram.

Meanwhile, Reuters citied Richard Aboulafia, analyst at consultancy AeroDynamic Advisory, saying that a collision with birds typically results in the plane landing in the nearest available field.  "You can lose control of the plane, but you don't fly wildly off course as a consequence," Mr. Aboulafia was cited as saying. 

According to Interfax, Kazakhstan's main transport prosecutor, Timur Suleimenov, told reporters in Astana that the plane's black box, which contains flight data to help determine the cause of a crash, had been found.

According to Kazakh officials, those aboard the plane included 42 Azerbaijani citizens, 16 Russian nationals, six Kazakhs and three Kyrgyzstan nationals.