The probe into the Azerbaijan Airlines crash in Kazakhstan is examining the conduct of air traffic controllers after the aircraft encountered difficulty, a source said.

The National Resistance Center (NRC) has obtained a letter from Turpal Ilyasov, the representative of Chechen leader Ramzan Kadyrov in Russia's Ural Federal District, containing instructions on how to comment on the crash of an Azerbaijan Airlines plane in Kazakhstan.

Azerbaijan Airlines flight J2-8243 caught fire as it tried to make an emergency landing in Aktau, southwestern Kazakhstan, on Wednesday. It was traveling from the Azeri capital Baku to Grozny, the capital of the Russian republic of Chechnya.

Russian President Vladimir Putin apologized to his Azerbaijani counterpart for what he called a "tragic incident" following the crash of an airliner.

Azerbaijan’s President Ilham Aliyev has accused Russia of accidentally shooting down an airliner on Christmas Day in a disaster that killed 38 people, and covering up the cause.

Survivors from the crash told ABC News that they heard and felt explosions outside the aircraft during the flight, after which the plane appeared to lose control.

Azerbaijan’s president Ilham Aliyev has accused Russia of shooting down a plane that crashed on Christmas Day, killing 38 people.

Azerbaijan has demanded that Russia admit its guilt over a Christmas Day plane crash that killed 38 people, the country's President Ilham Aliyev said on Sunday. The big picture: Russian President Vladimir Putin apologized to Aliyev for the Azerbaijan Airlines crash occurring in Russian airspace,

Azerbaijani President Ilham Aliyev said he was “upset and surprised” that Russian officials put forward murky causes instead of promptly taking responsibility.