Red Flag Raised

Please note that this claim may not be fully vetted.It may have significance in the Shi’ia Moslem beliefs that the 12th Imam will be revealing himself after hiding in a well since the 7th Century, but now is to emerge to carry out the victory of a Moslem world-wide Caliphate (implying, IMHO, that the Shi’ia think that an Armageddon-like battle could be approaching).
See: https://factcheck.afp.com/no-red-flag-revenge-was-not-raised-first-time-iran-mosque
Article states this explanation which arose after Trump had Soleimani killed by missile strike in 2020:
Why was the flag raised this time?It is rare for the red flag to be raised on this mosque outside the month of Muharram. “Due to the martyrdom of general Qassem Soleimani and his comrades, and after hearing the supreme leader calling for a harsh revenge, we unfurled this flag so that all (Shia) believers in the world and all the freedom fighters gather around this flag to avenge Qassem Soleimani’s blood unjustly shed,” Abadi told AFP. 
What does this flag mean?The flag bears the Arabic phrase, “Ya la-Tharat al-Hussein,” which can be translated in English as, “O ye avengers of Hussein.”
As Muhammad’s grandson, Hussein, is one of the most sacred figures of Shia Islam, in which he is the incarnation of justice. He was killed in the year 680 at the battle of Karbala, in present-day Iraq, by caliph Yazid’s troops.
This battle and Hussein’s martyrdom are the founding elements for Shia Islam, and mark a definitive schism with Sunni Islam. 
According to certain Iranian Shia traditions, “Ya la-Thara al-Hussein,” should be a rallying cry for believers upon the return of the Hidden Imam, the last of twelve imams recognized in Imamiyyah, the largest branch of Shia Islam.
How long will this flag remain on the dome?Certain articles claim that the flag will fly until the death of Soleimani is avenged. “It’s completely false,” the mosque administrator said.
Abidi said that the flag will fly “for a certain amount of time,” without providing a specific date.