Iran's civil aviation body said an error by air defence operators led to a Ukrainian passenger plane being shot down in January last year.
Iran's Revolutionary Guards shot down Ukraine International Airlines flight PS752 on January 8, killing all 176 people on board.
The aviation body report claimed air defence mistakenly identified the plane as a hostile target.
Ukraine's foreign minister said the report is a cynical attempt by Iranian authorities to cover up the true reasons for the incident.
The minister said, "What we saw in the published report today is nothing more than a cynical attempt to hide the true reasons for the downing of our plane,".