Russia has been blamed for shooting down an Azerbaijan Airlines plane that crashed in the Russian republic of Chechnya on Wednesday, killing 38 people.
Another 29 people survived the crash of the Embraer 190 aircraft that took off from the Azerbaijani capital Baku heading to Grozny in Chechnya before being diverted 450 kilometres east to Aktau in Kazakhstan because of fog.
Although Moscow officials tried to dampen speculation about the cause and Russian state-controlled television blamed a bird strike, unidentified sources attributed it to Russian air defences.
“No one claims that it was done on purpose. However, taking into account the established facts, Baku expects the Russian side to confess to the shooting down of the Azerbaijani aircraft,” Reuters quoted a source as saying.
Film shows the aircraft diving towards the ground at high speed before bursting into flames on landing.
Experts said aircraft usually glide toward the nearest airfield even with a loss of control after striking birds but in this case it flew off course.
Azerbaijan held a national day of mourning on Thursday for the victims with President Ilham Aliyev quoted by the BBC as saying: "This is a great tragedy that has become a tremendous sorrow for the Azerbaijani people.”
One source said preliminary results of an investigation showed the plane was struck by a Russian Pantsir-S air defence system after its communications were paralysed by electronic systems on the approach to Grozny.
Kremlin spokesman Dmitry Peskov said: "It would be wrong to put forward any hypotheses before the investigation's conclusions. We, of course, will not do this, and no-one should do this. We need to wait until the investigation is completed."
Azerbaijan is located in the South Caucasus region at the crossroads of Eastern Europe and Western Asia, bordering Russia, Georgia, Armenia and Iran.