What is the ruling on a congregation performing the Fajr prayer if it is held before its prescribed time, and is a re-prayer obligatory?

Prayer performed before its prescribed time is not valid and does not fulfill the obligation, for Allah Almighty says: "Indeed, prayer has been decreed upon the believers a ‫set ‫time." Therefore, one is not obligated to attend congregational prayer if they are praying before the time. Rather, it is obligatory to advise and alert them to this. The questioner should seek a mosque where prayer is performed at its proper time, or pray in congregation at home after the time has begun. If this is not possible, then he is excused for praying alone.