Bloomberg - An Iranian air defense unit that �forgot� to adjust its radar system triggered a chain of communication and human errors that led to the deadly downing of a Ukrainian passenger jet in January, according to a report from Iran�s Civil Aviation Organization.

Iran said it mistakenly shot down Ukraine International Airlines Flight 752 shortly after take-off, killing all 176 aboard. Decoding of the jet�s black boxes is expected to start July 20.

The plane was downed by two missiles, fired 30 seconds apart, from an air defense unit that mistook the jet for a cruise missile. An operator had forgotten to re-adjust the north direction on the radar system after moving to a new position, an error that contributed to misreading the radar�s data, according to the report published on CAO�s website on Saturday.

�The operator of the air defense system launched a missile at what it had detected as a hostile target without response from the command center,� CAO said in the report, adding that an unnamed person took action independently and without authorization from superiors.

The incident took place hours after Iran�s defense systems were put on high alert following the country�s missile attack on a U.S. air base in Iraq in retaliation for the killing of a top Iranian general by the order of President Donald Trump.

Six people have been arrested in connection with the incident, authorities said in June without giving details.