The following is the full text of the message issued on January 11, 2020, according to Khamenei.ir
In the Name of God, the Most Beneficent, the Most Merciful
After having been informed of the results of the investigation conducted by the General Staff of the Armed Forces pertaining to the Ukrainian passenger plane, and after it was proven that human error was involved in that incident, the grief stemming from the loss of the deceased from that sad incident became heavier for me.
First of all, I deem it necessary to express my genuine sympathy and my heartfelt condolences to the esteemed families of the dear victims and to ask God, the Exalted, to bestow patience, tranquillity and peace of mind on them. Secondly, I order that the General Staff of the Armed Forces pursue every case of possible negligence or error that may have been committed in this painful incident. Thirdly, I ask the managers and officials in charge to do everything in their power to prevent such incidents from recurring in the future.
May God, the Almighty and the Beneficent bestow His grace and mercy on the deceased, and may He shower patience and reward on their family members.
Sayyid Ali Khamenei
January 11, 2020