According to the Herat Police Chief Abd al-Raouf Ahmadi, some 500 people gathered in front of the Iranian Consulate on Saturday, protesting about their visa problems.
Ahmadi, quoted by Fars News Agency, said the protesters attacked the Consulate building and tried to burn it down.
Four police officers were wounded in the clashes which left one of the attackers dead as well, he added.
The reports are still mixed about number of casualties, with some locals saying two people were killed, one of them from the Police.
Pictures received from the Consulate after the attack showed the building was damaged and there were blood stains on the ground and walls.
SHI/SHI