JERUSALEM -- The U.N. agency for Palestinian refugees suspended aid to the Gaza Strip on Friday, accusing the territory's Hamas rulers of stealing a delivery of humanitarian supplies for the second time this week.
The announcement by the U.N. Relief and Works Agency deepened tensions between the international body that assists the majority of Gaza's 1.4 million people and the Islamic group that controls the coastal strip.
The crisis comes at a sensitive time. U.N. officials say Gaza's needs are especially dire in the wake of Israel's military offensive against Hamas, which killed nearly 1,300 people, displaced thousands and caused widespread destruction.
Israel holds parliamentary elections Tuesday. New opinion polls published Friday showed a close race, but predicted the nationalist Likud Party, which advocates an even tougher line against Hamas, would head the next coalition government.
In a statement, UNRWA said it had suspended aid deliveries to Gaza after the Hamas-run Ministry of Social Affairs stole 10 truckloads of flour and rice delivered to Gaza on Thursday. Earlier this week, Hamas police took thousands of blankets and food parcels meant for needy residents.
"Hamas has got to hand back all the aid that they have taken and they have to give credible assurances that this will not happen again. Until this happens, our imports into Gaza will be suspended," said UNRWA spokesman Chris Gunness.
He said the agency, which maintains "working level contacts" with Hamas, had filed a protest with the government. Gunness said UNRWA would continue to distribute aid from its existing supplies in Gaza, but that stocks were running thin.
"There is enough aid for days, not weeks," he said.
Some 80 percent of Gaza's 1.4 million people rely on the U.N. agency for food or other support.
In Gaza, Hamas Social Affairs Minister Ahmed al-Kurd dismissed Thursday's incident as a "misunderstanding" and expressed hope the dispute would soon be resolved.
"We welcome all aid, whether from UNRWA or international organizations," he said. "Any international organization that wants to help or build in Gaza, we have no conditions, come to Gaza, and we will provide security, safety and calm," he said.
The spat with Hamas created a challenge for UNRWA, which already has been pressuring Israel to ease its blockade of Gaza's borders to allow more aid into the area.
Most cargo into Gaza comes through Israeli-controlled crossings. Israel has largely closed the crossings since Hamas seized control of Gaza in June 2007. Israel fears supplies will reach Hamas, which it considers a terrorist group.
Israel unilaterally halted its devastating Gaza operation, meant to halt years of Hamas rocket attacks, on Jan. 18, and Hamas followed with its own separate announcement that it too would cease fire.
Egypt has been trying to broker a long-term truce. Hamas is demanding that Israel open Gaza's border crossings as part of any agreement. Israel, in turn, wants a halt to arms smuggling into Gaza, and is seeking the release of a captured soldier held by Hamas for more than two years.
The attempts to negotiate a cease-fire are unfolding in the shadow of Israel's national election, and the candidates have all been competing over who can take the toughest stand against Hamas.
The final opinion polls before the election predicted a close race, but showed voters clearly prefer hard-line parties.
In a TV interview Friday night, Likud leader Benjamin Netanyahu said he would seek a broad coalition if he wins, but would turn to "the nationalist camp" -- a reference to more hawkish parties -- in building a government. "We need a different way," he told Israel TV.
Netanyahu says no peace agreement with Hamas' rival, the moderate Palestinian leadership in the West Bank, is possible in the foreseeable future. Instead, he says he will try to jump-start the West Bank economy while continuing Israel's military occupation indefinitely. He also advocates a tough line against the rival Hamas government in Gaza.
AP correspondents Karen Zolka in Jerusalem and Ben Hubbard in Gaza City, Gaza Strip, contributed to this report.