Several aviation experts said they believe that a Russian defense system caused the Azerbaijan Airlines plane crash that killed 38 people on Christmas Day, according to the Associated Press. The flight was headed from Baku, Azerbaijan, to Grozny, Russia, but diverted course amid bad weather before crash landing near Aktau, Kazakhstan. The incident left 29 survivors, all of whom are injured, the AP reported. With investigations underway in Azerbaijan, Kazakhstan, and Russia, officials in those countries have urged against speculation about the crash’s cause. Russia’s aviation authority has suggested, nevertheless, that a bird strike could have played a role. But aviation experts seem to disagree. Mark Zee, founder of the aviation safety organization OPSGroup, told the AP that based on images of the plane, he is “90-99%” sure it was struck by a missile. Independent Russian military expert Yan Matveyev agreed that the plane’s tail appeared to have been struck by shrapnel from a missile like the ones used by Russia’s defense system. Meanwhile, the UK aviation security firm Osprey Solutions reportedly cautioned its clients that “Azerbaijan Airlines flight was likely shot down by a Russian military air-defense system.”