India and Laos have all to play for in the later match if they are to earn a spot as one of the top five second placed teams, Tehran Times reported.
Iran, who had already booked their place in the Finals after wins against Laos and India, took the game to Mongolia with Esmaeil Gholizadeh netting in the 24th minute, the-afc.com reported.
Mongolia fell further behind with Iran adding three more goals before the break through Yousef Mazraeh in the 33rd minute with Kasra Taheri scoring from the penalty spot 10 minutes later and Yaghoob Barajeh netting in the 44th minute.
Iran turned on the power in the second half leaving Bhutan without a chance to respond as the goals poured in through Abbas Kahrizi (54th), Abolfazl Moradi (73rd, pen), Gholizadeh (82nd) and Aliasghar Sheikholeslami (89th) to seal the win.
MNA