Hamas has threatened to shell a Gaza border crossing if Egypt and Israel open it to some 6,000 Palestinians stranded in the Egyptian Sinai.
The displaced persons, most of whom are affiliated with the rival Fatah faction, fled to Egypt during Hamas' brutal military takeover of Gaza last month.
Egypt is now anxious to send them back home, and Israel offered to help by opening the Kerem Shalom Crossing where the borders of Israel, Egypt and the Gaza Strip meet.
But The Jerusalem Post reported that Hamas officials told Egypt that if the plan is implemented, the group will open fire on the border crossing, even at the risk of killing thousands of fellow Palestinians.
Israel and Egypt are taking the threat seriously after Hamas shelled Kerem Shalom last week when Israel tried to use the crossing to get food into Gaza.