Azerbaijan Airlines plane crash, likely caused by Russian air defense, shines light on a glaring issue the Kremlin has long swept under the rug.

Russian President Vladimir Putin said Saturday that Russia’s air defense systems were active when an Azerbaijan Airlines flight attempted to land in Grozny, Chechnya on Wednesday.

On 25 December, 38 people died when an Azerbaijan Airlines flight, which had been due to land in Russia, crash-landed in Kazakhstan. The circumstances around the crash remain unclear, but limited evidence so far suggests it may have been damaged by missiles fired by a Russian air-defence system as it tried to land in Chechnya.