The UN says an alternative way of getting fuel to Gaza must be found urgently, warning of dwindling supplies needed to run hospitals, pick up garbage, pump water and treat sewage.
The appeal late Sunday by the UN Office for the Coordination of Humanitarian Affairs (OCHA) came two days after hundreds of Palestinians destroyed the fuel terminal at the main cargo crossing with Israel, the only entry point for fuel to Gaza. Officials say it could take months to repair the damage.
Israel has held Gaza's Hamas rulers responsible. The Islamic militant group has not commented publicly.
The closure comes at a time when Hamas is trying to break a decade-old blockade of Gaza by Israel and Egypt with mass border protests, with the largest crowd yet expected Monday.