An Azerbaijan Airlines flight that crashed in Kazakhstan on Christmas Day was downed by a Russian air defence system, a preliminary investigation has found, according to reports.

The Azerbaijan Airlines jet crashed near the Kazakh city of Aktau on Wednesday, killing 38 of the 67 people on board.

The Embraer 190 aircraft was supposed to fly north-west from the Azerbaijani capital Baku to the city of Grozny in Chechnya in southern Russia, but instead diverted far off course across the Caspian Sea.

Azerbaijani government sources have said that the plane was attacked by a Russian Pantsir-S air defence system on its approach to Grozny, according to AnewZ, an Azerbaijani news site.

The outlet also reported that the aircraft’s communication system was “completely paralysed”, causing it to disappear from radars in Russia’s airspace.

It only reappeared as it flew over the Caspian Sea shortly before crashing.

Four sources in Azerbaijan with knowledge of the investigation also told the Reuters news agency that the plane was downed by a Russian air defence system, corroborating AnewZ’s report.