The Israelis have said they will allow power plant fuel and medicines into the Gaza Strip on Tuesday, easing a blockade imposed after rocket attacks.
Gaza's only power plant depends on Israeli fuel
Defence Minister Ehud Barak agreed to ease the curbs for one day, hours after the territory's sole power plant shut down, plunging Gaza City into darkness.
But he later warned that Gaza remained a stronghold of "terrorists".
The UN has warned food aid to about 860,000 Gaza people could be halted within days because of the blockade.
The EU says Israel is "collectively punishing" the Hamas-run territory.
The BBC's Paul Wood reports from Gaza that the Israelis seem to have been stung into easing the blockade by the UN warning of a food shortage.
However, our correspondent adds, Gaza's underlying problem, its exclusion from the peace process under Hamas rule, remains.
Open for one day
Addressing a security conference, the Israeli defence minister said his country would continue striking at Gaza in response to militant attacks.
Israel says border closures will stop if the rocket attacks end
"I care more about our quiet than their quiet," he was quoted as saying by the Associated Press.
"Many terrorists are alive and breathing only because we try not to hit civilians."
Gaza's only power plant produces 27% of the territory's electricity needs, according to a recent UN report.
Israeli foreign ministry spokesman Arye Mekel told the BBC the easing of restrictions, which were imposed on Friday, was for one day only and the government would then review the situation.
While the Israelis said enough fuel would be allowed in to run a power station, they did not say for how long.
Israel earlier reacted angrily to its shutdown, saying it was still providing power to Gaza and putting its current contribution at nearly 70%.
Mr Mekel accused Hamas of "fabricating" the power shortage.
Bread and rockets
Israel imposed the blockade in retaliation for attacks on its territory by Gaza-based militants using rockets and mortars.
Generators are supplying critical power to hospitals
John Ging, head of the UN relief agency UNWRA, told the BBC he welcomed the easing of the blockade, saying the situation in Gaza was "desperate" and "collective punishment" was unjust.
UNWRA spokesman Christopher Gunness said earlier his agency was running short of nylon for plastic bags and fuel for vehicles and generators.
Petrol stations have been closed in Gaza and some bakeries have been unable to make bread.
Generators are being used to maintain critical power supplies to hospitals.
"There are reserves for two, maximum three, days for the functioning of hospitals in Gaza," Red Cross spokeswoman Michele Mercier told AFP news agency in Jerusalem.
"If our truck with medicine does not enter Gaza [on Tuesday], this can cause a major problem."
Before the Israeli announcement, Egyptian President Hosni Mubarak telephoned Israeli Prime Minister Ehud Olmert to warn him of the humanitarian effects of the blockade.
He also raised the possibility of reopening the Rafah crossing between Gaza and Egypt, which Israel insists should remain closed.
Arab League officials meeting in Cairo called for the UN Security Council to debate "the starvation, the siege and the darkness in Gaza".
The Security Council late on Monday announced that it would hold a meeting on Tuesday to discuss the situtation.
The UK said it did not support the Israeli blockade and called for all parties to work for the reopening of the crossings.
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