Palestinian boys play soccer after attending school Saturday in Jebaliya, northern Gaza Strip.
In one classroom, signs with the names of three 14-year-old boys killed in the fighting were set on their desks -- and their deskmates sat next to the empty seats as the teacher encouraged the class to talk about their experiences.
"It's very hard when one used to see 30 students in class, and after what happened, I see 27," their teacher, Bassam Salha, told the class at the U.N.'s Fakhoura Elementary school. "We lived three weeks in sadness. I want you students to help me to get out of the sad mood I am in now."
The reopening of schools, a week after a tentative cease-fire, marked a small step back to normalcy for Gaza's 1.4 million residents. Israel had launched a 22-day air and ground assault, aimed at stopping rocket fire by Gaza militants on southern Israel.
Some 280 children were among the 1,285 Palestinians killed in the offensive, according to the Palestinian Center for Human Rights. Thirteen Israelis, including three civilians, were also killed during the fighting.
Israeli Prime Minister Ehud Olmert has expressed regret over the deaths of civilians, but Israel blamed the deaths on Hamas, saying its fighters used civilians, schools and mosques to shield themselves.
The scores of schools run by the United Nations -- which are attended by 200,000 children -- reopened along with Gaza's public schools, which Hamas has run since seizing the territory in 2007.
"Getting these children back to school was our absolute priority," John Ging, Gaza head of the U.N. agency that cares for Palestinian refugees, told the Associated Press.
In one school, first-grade girls with white ribbons in their hair swept shattered glass from the courtyard. More than 30 U.N. schools were damaged in the fighting.
The schools were also used as makeshift refuges by tens of thousands of Gazans fleeing clashes between Israeli forces and Palestinian militants in border areas, and by others whose homes were destroyed in the fighting.
At the Fakhoura Elementary school in the town of Jebaliya, volunteers from an Islamic aid organization led the children through a series of songs and clapping games in the courtyard.
Talking to his students, Salha recalled the three lost classmates, calling one, Ahed al-Quddas a "very naughty student, but he was light-hearted." Another, Bashar Naji, "was always giving the right answers," he added.
One of Naji's friends spoke up.
"I don't know what I'm going to do after him -- he used to help me in answers and the others at the same time."
During the fighting, Palestinian militants fired rockets from next to the school, where hundreds of Gazans had huddled, according to witnesses. Israeli forces responded with mortars that hit near the school and killed 42 people, most civilians.
At the Asma elementary school in the Shati refugee camp, three blood stains and a large hole in the bathroom wall marked the spot where a Jan. 5 missile strike made a direct hit and killed three boys and teens, ages 10, 17 and 19. The three, who were among hundreds taking refuge at the school, were using their cell phones to light the way to the bathroom when struck, witnesses said.
Hundreds of students sat in the courtyard, eating U.N.-provided bread, cheese and cucumbers. Many had lost relatives.
Fifth-grader Noor Abdel-Ali, said two of her brothers were killed in the first day of air strikes. Suhaib, 30, was working at a police station that was bombed, and Yousef, 18, was in the Internal Security building when it was hit, she said.
"I feel alone because they used to come visit me at school," said Noor, 10. "My friends are around me here, but I'm still sad that they died."
Meanwhile, the Israeli Defense Ministry said it would ask the Cabinet at its weekly meeting Sunday to provide legal support to army officers in potential court cases resulting from the war's conduct.
Defense Minister Ehud Barak said that the war on Hamas Israel was exercising "the right, indeed the obligation, of any country, under international law to defend itself and its citizens."
Israeli, Palestinian and international human rights groups have said they are seeking to build a case that Israel violated the laws of war. The groups are focusing on suspicions that Israel used disproportionate force in its onslaught and failed to protect civilians.
Israel, which denies any violations, is gearing up to protect its soldiers from any attempted prosecution, including with Barak's motion to the Cabinet. The rights groups say it is too early to say if they would seek any such prosecution, and it is not clear at what court it could be attempted.
Half a dozen international aid groups called for the free passage of humanitarian aid and construction materials through Israel's border crossings with Gaza.
The Israeli army said more than 125 trucks a day -- on some days nearly 200 -- have entered Gaza since fighting ended on Jan. 17.
"We are looking at providing (aid) for months and even years to come," said Mohammed Ali Abu Najila of Oxfam told a news conference at Gaza City's Shifa Hospital. "Lives are hanging in the balance and they depend on unrestricted humanitarian access and increasing funding."
The border crossings are a central issue in efforts to work out a long-term cease-fire. Israel and Egypt had enforced a border blockade following the Hamas takeover in 2007, and have said they will only open the gates if Hamas accepts the deployment of border monitors, as a way of halting weapons smuggling.
Hamas spokesman Fawzi Barhoum said a Hamas delegation to Cairo would discuss this and other issues with Egyptian leaders to create a detailed agreement.