UN action came hours after the world body suspended food deliveries to Gaza and the Red Cross accused Israel of blocking medical assistance after forces fired on aid workers.
It also followed concerns of a wider conflict which flared as militants in Lebanon fired rockets into northern Israel.
The vote was 14-0, with the United States abstaining. Secretary of State Condoleezza Rice said the US "fully supports" the resolution but abstained "to see the outcomes of the Egyptian mediation" with Israel and Hamas, also aimed at achieving a cease-fire.
Israel and Hamas were not parties to the vote and it will now be up to them to stop the fighting.
But the text of the resolution was hammered out by the United States, Israel's chief ally, and by Arab nations that have ties to Hamas and the Palestinians in the Israeli-occupied territories.
As the Security Council took action late Thursday in New York, it was early Friday in Gaza and violence continued unabated - an Israeli airstrike flattened a five-storey building in northern Gaza, killing at least seven people, including an infant, Hamas security officials said.
It was one of more than 30 targets struck before dawn by Israeli warplanes. It was not immediately clear whether the owner of the destroyed house was linked to Hamas.
Militants in Lebanon fired several Katyusha rockets into northern Israel early Thursday, including one that tore through the roof of a nursing home and injured two people. Israel responded swiftly with mortar fire, raising the possibility of a two-front conflict.
With Friday's toll, nearly 760 Palestinians and 13 Israelis have died in the 13 days of fighting in Gaza, an assault launched by Israel in an attempt to halt rocket fire from the territory, controlled by the militant Islamic Hamas.
Hamas said it fired 25 rockets and 12 mortars at Israel on Thursday.
The conflict has left hundreds of thousands of Palestinians in Gaza increasingly desperate for food, water, fuel and medical assistance, and the situation was expected to worsen as humanitarian efforts fall victim to the fighting.
The Security Council resolution "stresses the urgency of and calls for an immediate, durable and fully respected cease-fire, leading to the full withdrawal of Israeli forces from Gaza."
It expressed "grave concern" at the escalating violence and the deepening humanitarian crisis in Gaza and emphasized the need to open all border crossings and achieve a lasting solution to the Arab-Israeli conflict.
It also calls on UN member states "to intensify efforts to provide arrangements and guarantees in Gaza in order to sustain a durable cease-fire and calm, including to prevent illicit trafficking in arms and ammunition and to ensure the sustained re-opening" of border crossings.
In addition, the resolution "condemns all violence and hostilities directed against civilians," calls for "unimpeded" humanitarian access to Gaza, and welcomes the initiative to open "humanitarian corridors."
Simon Horner, of the European Commission aid department, said 60 percent of Gaza's 1.4 million people have no electricity, and fewer people every day have access to clean water. The sewage system is in danger of a failing, which could lead to an outbreak of disease, and medical services were under severe stress.
"The inability of the UN to provide assistance in this worsening humanitarian crisis is unacceptable," said Michele Montas, a UN spokeswoman.
She said according to reports, the attack on the UN truck, which killed two Palestinian workers, took place during a three-hour humanitarian lull announced by the Israel Defense Force.
Four UN Relief and Works Agency local staff have been killed in the conflict.
In Geneva, the International Committee of the Red Cross said it would restrict aid operations to Gaza City for at least one day after one of its convoys came under Israeli fire at the Netzarim crossing during the three-hour lull in fighting Thursday. One driver was lightly injured.
The World Health Organization said 21 Palestinian medical workers have been killed and 30 more injured since Israel began its offensive.
The Israeli military said in a statement that it cooperates closely with foreign aid groups to help civilians, and said Hamas uses civilians as human shields.
The international Red Cross also accused Israel of hindering rescuers from reaching areas devastated in the battles. Ambulances could not get to the Zeitoun neighbourhood for four days because the Israelis had blocked access with large earthen barriers, officials said.
When they were allowed in on Wednesday, the rescuers "found four small children next to their dead mothers in one of the houses. They were too weak to stand up on their own. One man was also found alive, too weak to stand up," the ICRC said in a rare public statement.
"In all, there were at least 12 corpses lying on mattresses" in one of the houses.
During the lull in fighting on Thursday, Palestinian health officials dug out 35 bodies from several areas around Gaza that had been engulfed by battles or struck by Israeli air attacks since Israel launched its offensive against Hamas, said Moaiya Hassanain of the Palestinian Health Ministry.
At least 24 Palestinians were killed in Gaza on Thursday, including three elderly people fleeing their home, according to Hassanain. He estimated the death toll around 750, and UN officials say about half were civilians.
Three Israeli soldiers were killed in combat on Thursday, raising the number of soldiers killed in the conflict to 10, including one who died in a mortar strike before the ground invasion began. Three Israeli civilians have been killed by rockets.
Gaza militants unleashed 24 missiles at southern Israel on Thursday, wounding four people.
Egyptian-led diplomatic cease-fire efforts showed no immediate breakthroughs. Israeli representatives concluded talks in Cairo and returned home, one day after Hamas leaders reviewed the French-Egyptian plan that might offer a role in Gaza to the rival Palestinian Authority.
Israel's government said on Wednesday it viewed the proposal positively, but only if it guaranteed a halt to rocket fire on Israeli territory from Gaza and ensured Hamas cannot rearm. A Hamas official said the Islamic militant group was not ready to either accept or reject the plan.
But Mohammed Nazzal, a member of Hamas' Damascus-based political leadership, said, "We will never raise the white flag. I believe there are going to be fierce battles and the resistance factions will fight house to house, street to street and neighbourhood to neighbourhood."
Israel launched a ferocious air assault on Gaza December 27 to disable Palestinian militants and cripple the Hamas movement.
The Israeli military had no immediate comment on the shooting at the UN aid vehicle. UN spokesman Adnan Abu Hasna said the truck was heading toward the Erez border crossing to pick up supplies and had coordinated the delivery with Israel.
"We've been coordinating with them (Israeli forces) and yet our staff continue to be hit and killed," said Chris Gunness of UNRWA, which has been helping Gaza refugees since 1949, he said.
The deaths follow Israel's killing of at least 39 people at a UN school where hundreds of people had sought refuge from the relentless air and ground attacks. Israel said its troops were returning fire toward a squad of militants who fired mortars at its troops, then ran toward the school to hide among the refugees.
Two hours after Thursday's shooting on the truck, Israel ordered a three-hour halt in its offensive for the second day in a row to allow aid into the territory. Israeli military spokesman Peter Lerner said 89 trucks of food were unloaded, along with 83,000 gallons (315,000 liters) of fuel.
The two 3-hour breaks in the offensive provided rare windows for Gazans to buy from the dwindling supplies in the shops, and for rescuers to scour the ruins of entire neighborhoods for unreported casualties. Hassanain, the health official, said 20 more bodies were uncovered during Wednesday's mini-truce, in addition to the 35 found Thursday.
Israel had been braced for a resumption of hostilities on its northern border, anticipating that Hezbollah guerrillas in Lebanon would try to come to the aid of its Gaza ally, Hamas.
Nonetheless, the four rockets that hit the town of Nahariya created panic. "We are all a bit traumatized at the moment," said Sarit Arieli, 44, standing outside the nursing home that had been hit a few hours earlier.
Hezbollah, which fought Israel to a standstill in a 34-day war in 2006 and is now a key faction in the Lebanese government, denied it was responsible for the rockets.
Speculation focused on small Palestinian groups, which have rocketed Israel twice since the end of the Lebanon conflict. Lebanese Prime Minister Fuad Saniora condemned the attack.
Israeli leaders tried to keep a lid on northern tensions, calling it a one-time incident and welcoming Lebanon's condemnation.
