The Ukrainian Boeing crashed immediately after takeoff from the Iranian capital on 8 January, leaving all 176 people aboard killed. Three days later, Iran admitted that the jet had been mistakenly shot down by its armed forces who mistook it for a hostile cruise missile.
"We promise that those responsible for the crash of the Ukrainian plane will be sentenced before the one-year anniversary of this sad event," the deputy commander said, as cited by the Iranian broadcaster IRIB.
Six people were detained in Iran in June in connection with the Ukrainian plane crash case, three were soon let go.
The Iranian authorities have also signalled readiness to pay all necessary compensations to the families of victims, including nationals of Ukraine, Iran, Afghanistan, Canada, Germany, Sweden and the United Kingdom.
The plane crash took days after an escalation of the confrontation between Iran and the United States following the assassination of top IRGC commander Qasem Soleimani by US troops, to which Iran responded by hitting US military bases in Iraq.