Hojat-ol-Islam Movahednejad said 100 Istihlal groups will be dispatched to different parts of the country on Tuesday to sight the new moon.
He added that according to expert views, the new moon will most likely be sighted on Tuesday evening and, therefore, Wednesday will be the first day of the Hijri month of Shawwal that marks Eid al-Fitr.
Istihlal refers to efforts for sighting the new moon that determines the beginning of a new month on the lunar Hijri calendar.
In many Muslim countries, including Iran, moon-sighting committees are set up to confirm the start of Shawwal and the end of the fasting month of Ramadan.