I think mortar attack was right here, it's a very high hill and strategic military position that IDF holds in Gaza, like 90 meters elevation above the sea:

Martyr Izz El-Din Al-Qassam Brigades:
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Al-Qassam Brigades strike an enemy command and control site on Al-Sawrani Hill, east of Al-Tuffah neighborhood, east of Gaza City, with a number of mortar shells.