On a day of rising tension between Israel and international relief agencies, the Red Cross and the United Nations curtailed operations in the Hamas-ruled Gaza Strip on Thursday, and the U.N. Security Council approved a resolution calling for a cease-fire in the Palestinian territory.

In a 14-0 vote, with the United States abstaining, the Security Council called for an "immediate, durable and fully respected cease-fire" in Gaza that would lead to the full withdrawal of Israeli forces.

Arab and Western diplomats could not guarantee that the resolution would silence Israeli guns or stop Hamas from firing rockets into southern Israel. But they expressed hope that it would jolt the warring factions onto a new course.

Efforts to end the bloodshed were pushed by growing dismay over the toll Israel's 13-day-old offensive has taken on Gaza's civilian population and aid workers.

The International Committee of the Red Cross and the U.N. Relief and Works Agency said they were suspending movement of their staffers in the coastal enclave because of the risk posed by Israeli forces. The announcements came after Israeli gunfire Thursday killed two U.N. workers in a relief convoy and wounded a Red Cross driver.

The Red Cross issued an unusually tough statement accusing Israel of preventing ambulances from reaching wounded civilians in Gaza.

On Thursday, wounded survivors of an Israeli shelling of a family compound described a hellish two-day wait for medical help. When Red Cross workers finally arrived, they said, they found four small children, emaciated but alive, next to their mothers' corpses.

The Sammouni family's nightmare began when Israeli forces surrounded their Gaza City neighborhood and shouted Arabic commands over loudspeakers for everyone to leave to avoid being hurt.

It ended in a hospital across town as survivors of the shelling wept and told how wounded loved ones had bled and gone without food or drink until ambulances were allowed to reach them.

"There was a chance to save some of our wounded," Wael Fares Sammouni, a 39-year-old Palestinian vegetable merchant, said Thursday as he mourned the loss of his wife and five of their 10 children. "But they bled for too many hours."

The episode highlighted Gaza's dependence on relief agencies that have been struggling to keep its 1.5 million people alive and fed during the Israeli military assault.

Israel pressed its offensive Thursday, hitting weapons-smuggling tunnels and other targets from the air. But it kept ground troops on the outskirts of cities, delaying for now a deeper, full-scale ground assault on Hamas' urban strongholds.

Hamas fired 24 rockets into Israel, well below its peak.

In Gaza, Israel for a second day briefly suspended its offensive to give people a three-hour break to stock up on food and other essentials or move to safer places.

Just before the pause, the U.N. relief agency said the gunner of an Israeli tank opened fire on one of its food convoys, killing a Palestinian driver and another U.N. employee in their truck.

A U.N. spokesman, Adnan Abu Hasna, said the agency had coordinated the convoy with Israel and that the vehicle was marked with a U.N. flag and insignia.

The U.N. agency provides food aid to about half of Gaza's residents and runs dozens of schools and clinics in the impoverished Palestinian enclave. Israeli fire has hit two of the U.N. schools this week, killing more than 45 Palestinians who had sought refuge inside.

Red Cross officials said one of their drivers was wounded Thursday by Israeli gunfire on a convoy of 13 ambulances during the three-hour lull, forcing them to abandon an emergency call to the embattled city of Rafah in southernmost Gaza.

Israel says it is trying to stop rocket attacks on its border communities by Hamas, an Islamic group that seized control of Gaza in 2007 from a rival Palestinian faction.

More than 750 Palestinians have been reported killed in Gaza since the Israeli offensive began Dec. 27. Palestinian medical officials say more than one-third of the dead are women and children.

At least 11 Israelis have been killed, eight of them soldiers.

Criticism of the offensive on humanitarian grounds has risen since Israeli ground troops entered the territory Saturday after eight days of airstrikes. The fighting has trapped much of the population in besieged neighborhoods and worsened already acute shortages of food, fuel, water, electricity and medical supplies.

In several instances, wounded Gazans have been forced to wait hours or even days for ambulances.

The discovery of corpses and underfed children in the Sammouni family's homes, in the Zeitoun neighborhood on the edge of Gaza City, came as the lull in the offensive gave medical workers their first chance to move through the territory with relative ease.

In a pointed statement issued by its Geneva headquarters, the Red Cross accused Israel of preventing ambulances from reaching the neighborhood from Sunday to Wednesday. It called the delay "unacceptable" and said the Israeli military had failed to meet obligations to care for the wounded in combat areas.

Pierre Wettach, a Red Cross representative, called the incident "shocking."

"The Israeli military must have been aware of the situation but did not assist the wounded," he said.

The Israeli military did not comment directly on the allegation. In a statement, it said the army "has demonstrated a willingness to abort operations to save civilian lives and to risk injury in order to assist innocent civilians."

"Any serious allegations made against the [army's] conduct will need to be investigated properly, once such a complaint is received formally," the statement added.

The Zeitoun neighborhood came under Israeli attack in the first hours of the ground offensive Saturday. The military said its forces were after Hamas militants, but a spokesman had no specific information on individual houses that were targeted.

Fatima Sammouni, a 37-year-old mother of six boys, said Israeli soldiers arrived Sunday and ordered her extended family to leave their two-story stone houses on Salahuddin Street.

Her immediate family stayed put that night but, spurred by repeated Israeli warnings, ventured about 20 yards into the street Monday and slowly approached an Israeli tank. They waved white pieces of cloth, she said.

Suddenly the tank gunner and soldiers on the ground opened fire, she said, "like rain -- bullets and shells from all directions." Her husband and his brother were killed, and she suffered shrapnel wounds in the chest.

She retreated with her sons to the home of a relative, but the army kept shelling, she said. Her oldest sons, 15 and 17, were killed, along with the relative; the next oldest boys, 13 and 14, were wounded.

"I tried to call for help, but the telephone line went dead," she said. Her 14-year-old crawled to another house and telephoned a radio station to plead for help.

She said she lost consciousness the next day, bleeding and overcome by grief and fear.

It would be 24 hours more before help arrived.

A team of four Palestine Red Crescent ambulances accompanied by Red Cross representatives rescued her from the house and found three bodies there. Twelve other bodies were pulled from the rubble of Wael Fares Sammouni's house, along with an adult and four children who were too weak to stand, the Red Cross said.

Because of berms built by Israeli forces, the ambulances could not get close to the houses, so the children and the 18 wounded had to be evacuated in donkey carts.

Fatima Sammouni awoke from her nightmare in Gaza City's Al Quds Hospital. She wept as she told her story, seated on a hospital bed with her youngest boys, Sameh, 3, and Ahmad, 18 months.

"Why were we not allowed to leave?" she asked. "We did not have rockets or weapons."