The Northern Alliance was composed of Sunnis essentially. And on certain occasions, they even fought Shia Hazara groups. Iran backed both these parties despite their occasional infighting. Have you not seen how Ismail Khan, a Sunni, was peacefully escorted by to Iran by the Taliban?
I would advise into falling into this trap concocted by the zionists, the US and their clients, which consists in interpreting Iranian policy as well as the Afghan theater in sectarian terms (in fact, the ethnic factor has prevailed over confessional divisions in Afghanistan). Nobody would benefit from these sorts of tensions except the common enemies of Iran, Pakistan, Afghanistan, China and Russia.