All 176 people on the Ukraine International Airlines (UIA) flight died in the crash this week just after take-off from Tehran on a flight to Kiev.
"The Islamic Republic of Iran deeply regrets this disastrous mistake," President Hassan Rouhani wrote on Twitter. "My thoughts and prayers go to all the mourning families. I offer my sincerest condolences."
Foreign Minister Mohammad Javad Zarif offered Iran's "profound regrets, apologies and condolences to our people, to the families of all victims, and to other affected nations."
"A sad day. Preliminary conclusions of internal investigation by Armed Forces: Human error at time of crisis caused by US adventurism led to disaster," he tweeted.