Palestinians walk in front of a destroyed building after an Israeli air strike in Gaza City on Friday. (Hatem Moussa/Associated Press)

The United Nations will resume shipments of food and supplies to Gaza "as soon as possible" after receiving assurances from Israel that it is not being targeted, a UN spokesperson said Friday.

"The UN received credible assurances (from Israel) that the security of UN personnel, installations and humanitarian operations would be fully respected," spokeswoman Michele Montas told reporters.

"On this basis, UN staff movements, suspended yesterday, will resume as soon as possible."

The United Nations Relief and Works Agency (UNRWA) suspended deliveries to Gaza on Thursday after a UN delivery truck and medical convoy were fired on. Two drivers were killed. It's not clear where the fire came from, but the Israeli army is investigating.

The Israeli assurances included working to improve liaison and more effective internal co-ordination within the Israeli defence forces, she said.

Earlier Friday, the Israeli government said it would continue its military offensive in the Gaza Strip despite a recent United Nations Security Council resolution calling for an immediate ceasefire.

Prime Minister Ehud Olmert's office issued a statement saying continued rocket fire by Gaza militants on Israeli targets shows the council's call for a ceasefire "is not practical."

As such, the Israeli military "will continue acting to protect Israeli citizens and will carry out the missions it was given."

The statement was Israel's first official response to the resolution. Passed late Thursday in New York, it calls for an "immediate and durable" ceasefire between Israel and Hamas in the Gaza Strip.

Israeli towns hit

Attacks on targets on either side of the Israel-Gaza border continued overnight, just hours after the 15-member council made the call for an immediate end to the conflict.

Israeli aircraft struck up to 50 targets in the Palestinian territory by mid-morning, leaving at least 13 people dead. A five-storey building in the northern Gaza town of Beit Lahiya was flattened in one attack, killing seven including an infant, according to Hamas security officials.

Meanwhile, rockets continued to fly out of Hamas-controlled Gaza into southern Israel, striking the towns of Beersheba and Ashkelon. There were no immediate reports of casualties.

"Here at the Israeli-Gaza border, there is absolutely no indication of a ceasefire, despite the resolution that was passed last night," the CBC's Nahlah Ayed reported from the scene.

The UN Security Council resolution passed Thursday after key Arab and Western countries reached agreement on the language, which calls for a full Israeli withdrawal from the Palestinian territory and for arrangements to prevent arms smuggling to Gaza.

It also calls for the reopening of border crossings and the "unimpeded" provision of aid for the territory's 1.4 million residents.

'Not interested' in ceasefire: Hamas

Hamas ignored the diplomatic effort Friday, saying it "is not interested" in the ceasefire "because it does not meet the demands of the movement," according to a Hamas envoy to Lebanon, Osama Hamdan, in an interview with Al Arabiya.

However, a Hamas delegation left Gaza for Cairo on Friday to take part in talks on a Egypt-France-backed truce proposal, said an official with the Palestinian militant organization. He didn't say how the group got across the border.

It wasn't immediately clear what Hamas's demands are. The group has consistently said it wants border crossings into Gaza reopened.

A spokesman for the Islamic militant and political organization echoed Hamdan's sentiments, saying Hamas wasn't consulted during the process and the UN failed to consider the interests of the Palestinian people.

Palestinians clear rubble from a building next to the site where an Israeli missile strike destroyed a building used by the Islamic group Hamas in the Zeitoun neighbourhood in Gaza City on Friday. (Hatem Moussa/Associated Press)

"This resolution doesn't mean that the war is over," Hamas spokesman Sami Abu Zuhri told Al-Jazeera.

"We call on the Palestinian fighters to mobilize and be ready to face the offensive, and we urge the Arab masses to carry on with their angry protests."

A third Hamas spokesman, however, said the group was "studying" the resolution, according to Reuters.

Israel's top leaders were to meet Friday to discuss the ceasefire and the possibility of expanding Israel's 14-day-old offensive in Gaza. The likelihood that the Jewish state would agree to a ceasefire, at least in the immediate future, appeared dim.

"Israel has acted, is acting and will act only according to its considerations, the security needs of its citizens and its right to self-defence," Foreign Minister Tzipi Livni said in a statement issued Friday, according to Reuters.

30 dead in attack: UN report

Also Friday, a report by the UN Office for the Coordination of Humanitarian Affairs (OCHA) said at least 30 people, mostly members of the Samouni clan, were killed when a Gaza building was hit by Israeli shells last weekend.

Survivors told the authors of the report that Israeli soldiers had advised them to leave their homes and go to a building in Gaza's Zeitun district on Sunday. That building was hit by shells the next day, said the report.

The report offered no evidence that the attack was deliberate.

Israeli military officials denied soldiers warned civilians to go to another building.

"We don't warn people to go to other buildings. This is not something we do," said spokeswoman Maj. Avital Leibovitch. "We don't know this case. We don't know that we attacked it. It's not confirmed that we attacked it."

Another Israeli military spokesman, Maj. Jacob Dallal, said an investigation of the UN allegations showed the building was not deliberately targeted. "What we understand there was no pinpoint attack on that building in question. There is a lot of exchanges of fire. Gaza is a war zone. It's combat."

U.S. abstains from vote

Neither Israel nor Hamas were parties to the vote on the UN resolution, whose details were largely negotiated by Arab nations with ties to Hamas and those living in the Palestinian territories in Israel, along with the United States.

The U.S., a permanent member with veto power on the council and Israel's staunchest ally, was the lone country to abstain from the vote.

Smoke caused by explosions from Israeli military operations on the outskirts of Gaza City, as seen from the Israel-Gaza border on Friday. (Ariel Schalit/Associated Press)

U.S. Secretary of State Condoleezza Rice said Washington wanted to see what would emerge from Egyptian mediation efforts to end the conflict, but she added her country backed the text of the resolution, despite its abstention vote.

After the vote, Rice called the resolution "a step toward our goals," but laid the blame for the outbreak of hostilities squarely on Hamas rocket attacks, which restarted shortly after a six-month truce between the two sides expired last month.

"We must establish an international consensus that Gaza must never again be used as a launching pad for rockets against Israel," she told the council Thursday night.

Egypt, which helped broker the earlier truce between Israel and Hamas, is expected to try to convince both sides to accept the ceasefire. Hamas is slated to send some of its political leaders to Cairo on Saturday for talks.

The Palestinian death toll since the Israeli assault began has now exceeded 760, including about 350 civilians, according to Gaza medical officials and UN estimates. More than 3,000 Palestinians have been wounded, according to the Associated Press.

Thirteen Israelis, including three civilians, have been killed.

Among the dead was a Ukrainian woman, the first foreigner to die in the fighting, according to Gaza Health Ministry official Dr. Moaiya Hassanain. He said the woman was married to a Palestinian doctor who trained in Ukraine and returned with her to Gaza.

Her two-year-old son was also killed Thursday in tank shelling east of Gaza City, he said.

On Thursday, up to three rockets were launched into northern Israel from Lebanon, wounding two people when one landed on a nursing home in the town of Nahariya, about eight kilometres south of the Lebanese border.

Israel launched its military campaign with a series of air strikes on Dec. 27, followed by a ground incursion by thousands of troops into Gaza, in response to the resumption of Hamas rocket attacks on southern Israel.

UNRWA has said about 20,000 Palestinians have been displaced by the violence and most of Gaza is without electricity.

Sewage lagoons are filling up because pumps don't have power to run, while hundreds of thousands of people are without running water. The main power plant can't resume full operations because it is too damaged.

With files from the Associated Press