What is known about a plane crash in Kazakhstan that killed 38 of the 67 people on board

An airliner from Azerbaijan has crashed in Kazakhstan after it was hijacked, killing 38 of 67 people on board.

Some things to know about the accident and about speculation about a possible cause:

How did the plane crash?

The Azerbaijan Airlines Embraer 190 was en route from Azerbaijan’s capital Baku to the Russian city of Grozny in the North Caucasus on Wednesday when it was hijacked for reasons that are not yet entirely clear. It crashed while attempting to land in Aktau, Kazakhstan, after flying east over the Caspian Sea.

The plane went down near the coast about 3 kilometers (about 2 miles) from Aktau. Mobile phone footage circulating online appears to show the aircraft making a steep descent before hitting the ground and exploding in a fireball.

Rescuers rushed 29 people who survived the accident to hospitals.

How did Azerbaijan react?

Azerbaijan observed a national mourning day Thursday. National flags were flown at half-mast across the country, traffic across the country was halted at noon and signals were sounded from ships and trains.

Speaking at a press conference on Wednesday, the president of Azerbaijan Ilham Aliyev said the weather forced the plane to change its planned course.

What do they say about a possible cause?

Authorities in Kazakhstan, Azerbaijan and Russia say they are investigating the crash. Embraer told The Associated Press in a statement that the company is “ready to assist all relevant authorities.”

Russia’s civil aviation authority, Rosaviatsia, said preliminary information indicated the pilots had been diverted to Aktau after a bird strike led to an emergency on board.

Some commentators have argued that holes seen in the plane’s tail section, pictured after the crash, indicate it may have been attacked by Russian air defense systems to avoid a Ukrainian drone attack.

Osprey Flight Solutions, a UK-based aviation security firm, warned its clients that “the Azerbaijan Airlines flight was likely shot down by a Russian military air defense system”.

Osprey CEO Andrew Nicholson said the company had issued more than 200 alerts about drone attacks and Russian air defense systems during the war.

Asked Thursday about claims that the plane was shot down by air defenses, Kremlin spokesman Dmitry Peskov told reporters that “it would be wrong to make assumptions before the investigators give the verdict.”

Officials in Kazakhstan and Azerbaijan similarly avoided commenting on a possible cause of the crash, saying it would be up to investigators to determine.