Palestinian rocket attacks on Israel have increased since Hamas took control of the Gaza Strip in June.
Israel responded by largely closing off the territory and its 1.5 million people from the outside world.
It began reducing fuel supplies to Gaza last month and plans to begin scaling back electricity from Sunday.
Israel's supreme court ruled on Friday that the Israeli government can continue cutting fuel supplies to residents of Gaza but must postpone the planned electricity cut.
The ruling was in response to a legal challenge from a coalition of human rights groups that claims the policy constitutes collective punishment.
Gaza is dependent on Israel for all of its fuel and about half its electricity.
In January 2006, Hamas were democraticaly elected following Palestinian parliamentary elections in which they took 76 of the 132 seats in the chamber.