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Israel delivered fuel for Gaza's power plant on Tuesday, partially lifting a blockade it had imposed last week in response to a sharp increase in rocket attacks by Palestinian militants.

Five Israeli tanker trucks parked at the Nahal Oz crossing on the Gaza border pumped 700,000 liters of fuel to the other side, enough to provide electricity to Gaza City for two days. Three more trucks delivered cooking gas, and a shipment of medicine was to be delivered later in the day.

In all, Israel has promised three fuel deliveries over three days, for a total of 2.2 million liters, enough to keep the power plant running for a week, said Kanan Obeid, head of Gaza's energy authority.

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Israel had sealed Gaza on Tuesday, halting fuel shipments. Three days later, Gaza's only power plant, which provides electricity to about one-third of Gaza's 1.5 million residents, shut down. Other areas of Gaza are supplied directly by Israel and Egypt, neither of which cut off service.

On Monday, after Gaza's Hamas government and aid agencies warned of an impending humanitarian crisis, Israel decided to ease the blockade.

"We think Hamas got the message," Foreign Ministry spokesman Arye Mekel said Monday after Israel announced it was easing the closure. "As we have seen in the past couple of days, when they want to stop the rockets, they can."

However, three rockets were fired early Tuesday, causing no injuries.

Mekel said enough fuel would be shipped to power the Gaza electric plant for a week, as well as fuel for hospital generators and cooking gas, along with 50 truckloads of humanitarian aid, including medicine.

Hamas spokesman Sami Abu Zuhri dismissed the decision. "This does not mean the end of the siege on Gaza," he said, pledging to continue to fight "until we break the siege."

Ahmad Ismail, 44, a Gaza City merchant, also played down the Israeli gesture.

"This is a painkiller. They are not solving the problem, the problem is there, it exists and it is going to deteriorate day after day," he said. "The only solution for Gaza's problems is to lift the blockade and not to have this cosmetic solutions."

Raising a possible solution, moderate Palestinian President Mahmoud Abbas offered to take control of the Gaza crossings from the Palestinian side. One of the reasons Israel closed the crossings was its refusal to deal with Hamas officials in Gaza.

Hamas spokesman Fawzi Barhoum said Hamas would study Abbas' proposal. If implemented, it would give Abbas his first foothold in Gaza since Hamas ran his forces out in June. Israeli officials refused to comment.

Even after agreeing to the shipment, Israeli Defense Minister Ehud Barak maintained a tough tone.

Speaking at the annual Herzliya Conference on security, Barak called for increased pressure on Gaza. He said he was prepared to hit Gaza to restore calm in Israeli towns battered by rockets from Gaza. "I care more about our quiet than their quiet," he said.

Israeli Prime Minister Ehud Olmert strongly defended the blockade. He told legislators from his Kadima Party, "As far as I'm concerned, Gaza residents will walk, without gas for their cars, because they have a murderous, terrorist regime that doesn't let people in southern Israel live in peace."

Gaza's Hamas government issued emotional appeals to the Arab world, and demanded that Egypt open its border with Gaza to allow in supplies. "We are asking Arab and Muslim nations not to leave the Palestinians alone to face the terrorist country of America and the Zionist entity," said Gaza's Hamas strongman, Mahmoud Zahar, in a televised speech.

During the past seven months, since Hamas' violent takeover of Gaza, Egypt joined Israel in severely restricting access to Gaza, largely keeping its border terminal closed. An opening of the Gaza-Egypt border would mark a victory for Hamas, enabling it to claim credit for restoring the flow of supplies and stabilizing its rule.

However, it appeared unlikely Egypt would comply, since it's concerned about a spillover of Hamas-style militancy into its territory if the border is open. Instead, Egyptian President Hosni Mubarak called Barak and urged him to ease restrictions, and Barak agreed.