Media outlets reported that Sari, a senior security official under Afghanistan’s former government, was shot after leaving his workplace on Valiasr Street in Tehran.
He was hit in the head, taken to hospital, but later died from his injuries.
Iranian authorities have not yet released further details about the motive or suspects involved.
Sari was known as a prominent opponent of the Taliban and remained outspoken against the group after the collapse of the former Afghan government.
He reportedly maintained close contact with former Afghan security personnel living in Iran and was active in advocating for the rights of ex-military members, many of whom are based in the country.
He is the second former Afghan military commander opposed to the Taliban to be killed in Iran. Earlier, Marouf Gholami, a political and military figure close to anti-Taliban leader Ismail Khan, was shot dead at his office in Mashhad in September.
