Police say the unidentified man doused himself with gasoline before lighting himself on fire on Friday outside the gate of the embassy. The man suffered burns all over his body and was taken to a hospital.
Pol Lt Col Noppadol Samart says the man was protesting Friday's presidential vote in Iran, though he did not know exactly what about the election the man was opposed to.
Iranians are voting in the first presidential election since the country's nuclear deal with world powers. The election is largely viewed as a referendum on the current president's more moderate policies as well as economic issues.