What we know so far about the Azerbaijani airline crash that killed more than 35 people
Russia's aviation chief said a Ukrainian drone attack was underway in the region where the crash took place
A Russia-bound Azerbaijani airliner crashed in Kazakhstan on Wednesday after being diverted, killing 38 of 67 people on board. Some experts alleged that the plane went down after being hit by Russian air defence systems.
Russia's aviation chief said on Friday that a Ukrainian drone attack was underway in the Russian region but didn't comment on statements by an Azerbaijani lawmaker and some aviation experts, who blamed the crash on Russian air defences responding to a Ukrainian attack.
Here's what is known so far.
How did the plane crash?
The Azerbaijan Airlines' Embraer 190 aircraft was en route from Azerbaijani capital Baku to the Russian city of Grozny in the North Caucasus on Wednesday when it was diverted for reasons that aren't yet fully clear.
It crashed while making an attempt to land in Aktau, Kazakhstan, after flying east across the Caspian Sea.
The plane went down near the coast about three kilometres from Aktau. Cellphone footage circulating online appeared to show the aircraft making a steep descent before hitting the ground and exploding in a fireball.
Rescuers rushed the 29 people who survived the crash to hospitals.
Azerbaijan Airlines on Friday blamed the crash on unspecified "physical and technical interference" and announced the suspension of flights to several Russian airports. It didn't say where the interference came from or provide any further details.
Two passengers and one crew member on the plane told Reuters that they heard at least one loud bang as it approached its original destination of Grozny.
How did Azerbaijan react?
Azerbaijan observed a nationwide day of mourning on Thursday. National flags were lowered across the country, traffic stopped at noon and signals were sounded from ships and trains.
Speaking at a news conference on Wednesday, Azerbaijani President Ilham Aliyev said it was too soon to speculate on the reasons behind the crash but said that the weather had forced the plane to change from its planned course.
"The information provided to me is that the plane changed its course between Baku and Grozny due to worsening weather conditions and headed to Aktau airport, where it crashed upon landing," he said.
Ukrainian drone attack was underway
Russia's aviation chief, Dmitry Yadrov said that as the plane was preparing to land in Grozny in deep fog, Ukrainian drones were targeting the city, prompting authorities to close the area to air traffic.
Yadrov said that after the captain made two unsuccessful attempts to land in Grozny, he was offered other airports but decided to fly to Aktau in Kazakhstan, across the Caspian Sea.
"The situation in the area of Grozny airport was quite difficult," he said in a statement. "There are many circumstances that it's necessary to investigate jointly."
Ukrainian drones have previously attacked Grozny and other areas in the country's North Caucasus.
What do officials, experts say about a possible cause?
Kazakhstani, Azerbaijani and Russian authorities say they are investigating the crash.
Embraer, which is a Brazilian aircraft manufacturer, told The Associated Press in a statement that the company is "ready to assist all relevant authorities." Brazil has sent three air force investigators to Kazakhstan to "provide technical support" in a probe of the crash.
While officials remained tight-lipped, an Azerbaijani lawmaker directly pointed the finger at Russia.
Rasim Musabekov told the Azerbaijani news agency Turan that the plane was fired upon in the skies over Grozny and urged Russia to offer an official apology.
Some aviation experts say the holes seen in the plane's tail section after the crash indicate that it could have come under fire from Russian air defence systems fending off a Ukrainian drone attack.
White House national security spokesperson John Kirby told reporters on Friday that the U.S. has "seen some early indications that would certainly point to the possibility that this jet was brought down by Russian air defence systems," but refused to elaborate, citing an ongoing investigation.
Mark Zee of OPSGroup, which monitors the world's airspace and airports for risks, said that the analysis of the fragments of the crashed plane indicate with a 90 to 99 per cent probability that it was hit by a surface-to-air missile.
Osprey Flight Solutions, an aviation security firm based in the United Kingdom, warned its clients that the "Azerbaijan Airlines flight was likely shot down by a Russian military air-defence system."
Osprey CEO Andrew Nicholson said the company had issued more than 200 alerts regarding drone attacks and air defence systems in Russia during the war.
FlightRadar24 said in an online post that the aircraft had faced "strong GPS jamming" that interfered with flight tracking data allowing planes' flight path to be monitored. Russia has extensively used sophisticated jamming equipment to fend off drone attacks.
No definitive word
Yan Matveyev, an independent Russian military expert, noted that the images of the crashed plane's tail show damage compatible with shrapnel from the Russian Pantsir-S1 air defence system.
It's unclear why the pilots decided to fly hundreds of kilometres east across the Caspian Sea instead of trying to land in Russia after the plane was hit, he said, adding that they probably faced restrictions on landing at a closer venue and may have thought that the damage was not critical.
In Azerbaijan, online newspaper Caliber also claimed that the airliner was fired upon by a Russian Pantsir-S air defence system and also had its systems affected by jamming equipment as it was approaching Grozny.
The paper questioned why Russian authorities failed to close the airport despite the drone attack in the area on Wednesday, and why they didn't allow the plane to land in Grozny or other Russian airports nearby after it was hit.
Asked Thursday about the claims that the plane had been fired upon by air defence assets, Kremlin spokesperson Dmitry Peskov told reporters that "it would be wrong to make hypotheses before investigators make their verdict."
Other officials in Kazakhstan and Azerbaijan have similarly avoided comment on a possible cause of the crash, saying it will be up to investigators to determine it.
With files from Reuters