Israel cut off the only source of fuel to Gaza's 1.4 million people Thursday after a deadly Palestinian raid on the Israeli depot, deepening the seaside territory's hardship.

Gaza's Hamas rulers warned more attacks will follow, as resentment grows over a months-old Israeli blockade.

The fuel cutoff that followed the brazen daylight attack on the only fuel transfer point into Gaza brought charges that Islamic extremists were trying to provoke another round of violence with Israel, while putting Israel in the untenable position of appearing to cause a humanitarian crisis.

Though some Israelis demanded that Israel halt all supplies to Gaza, Israeli defense officials indicated the cutoff would not last past the weekend.

Hamas spokesman Sami Abu Zuhri said Wednesday's attack was only "the beginning of the eruption" against the blockade.

Hundreds of demonstrators gathered at the main intersections of Gaza City to protest the Israeli blockade and economic sanctions. "Rescue Gaza, lift the siege imposed on Gaza," read signs raised at one junction.

Abu Ahmed of Islamic Jihad said the attack deliberately targeted the fuel depot, where he said Gazans are forced to wait for hours for supplies strictly limited by Israel.

"This fuel (from Israel) is dipped in humiliation," he said. "If their fuel means humiliation for us, we don't want it."

After the deadly gunfire attack shattered the relative calm of the past month, Israel sent tanks, troops and aircraft into Gaza, killing at least eight Palestinians, including three civilians.

Though Israel pulled out of Gaza in 2005, it remains the main source of imports into the impoverished territory. Fuel and cargo enter and exit Gaza through two crossing points with Israel, and a third is the main passage for people. The only direct crossing between Gaza and Egypt is usually closed, as Egypt cooperates with the boycott of the Hamas regime imposed by Israel and the West.

Hamas is threatening to crash through the Egyptian border wall again, after a January breakout allowed hundreds of thousands of Gazans to stream into Egypt for nearly two weeks. About 200 Gazans demonstrated at the Egyptian border Thursday.

Human rights groups maintain that Israel is still technically the occupier of Gaza, despite its pullout, holding Israel responsible for the hardships faced by the Palestinians there. Israel has pledged to prevent a humanitarian crisis, while following a policy of gradually trying to disengage from Gaza.

The difficulty for Israel in cutting off fuel supplies to Gaza was evident in January, when Hamas invited TV networks to broadcast live as they shut down Gaza City's only electric power plant, plunging the city into darkness.

Though Israel insisted it was supplying enough fuel to produce electricity in Gaza and accused Hamas of staging an artificial crisis, pressure forced resumption of regular fuel deliveries within days.

The infiltration also served as a reminder that Israel, which is conducting peace talks with the rival Palestinian government of President Mahmoud Abbas, would not implement a deal as long as Hamas rules Gaza.

Israeli Foreign Ministry spokesman Arye Mekel said the raid would not disrupt peace talks. The two sides hope to reach a final peace deal by the end of the year.

"We decided that we will continue to talk and will not let terrorists have a veto voice on the talks with the pragmatic forces," Mekel said.

An Israeli think tank reported Thursday that the Hamas military buildup is at its peak, despite the blockade.

The Intelligence and Terrorism Information Center said Hamas has 20,000 armed men and has acquired longer-range rockets and advanced anti-tank weapons.

It also said Iran and Syria supply Hamas with weapons, technical know-how and training.

The center has close links to Israel's defense establishment, and some of the material in the report was based on data from the Shin Bet security agency.