The children of the Attar clan have lived through three wars in just over five years, each time fleeing their homes as Israel bombarded their neighborhood in the Palestinian Gaza Strip.

Their psychological scars show. Some act out, others cling to their mothers or withdraw, like 12-year-old Ahmed who sat by himself Monday on a bench in the courtyard of a U.N. school where his family once again sought shelter.

"They bombed very close to my house," said the boy, looking down and avoiding eye contact. "I'm scared."

Experts said it will be increasingly difficult to heal such victims of repeated trauma.

"For the majority of the children (in Gaza), it is the third time around," said Bruce Grant, the chief of child protection for the Palestinian territories in the United Nation's children's agency, UNICEF. "It reduces their ability to be resilient and to bounce back. Some will not find their way back to a sense of normalcy. Fear will become their new norm."

The Attar clan lives in Atatra, a neighborhood in northeastern Gaza, just a few hundred meters from Israel. Gaza militants often launch rockets at Israel from border areas, turning them into flashpoints and frequent targets of Israeli strikes.

Residents of Atatra fled their homes in Israel's three-week military offensive in the winter of 2008-2009, during a week of cross-border fighting in November 2012 and again over the weekend.

After Israeli aircraft dropped leaflets over Atatra on Saturday warning residents to leave, sisters Mariam and Sada Attar bundled a few belongings into plastic bags and rushed out of their homes. They had 10 children in tow, as well as Mariam's husband Omar, who she said suffers from stress-induced psychological disorders and can no longer function normally.

The families sought shelter in the same U.N. school where they stayed during the previous two rounds of fighting. In all, 20 U.N. schools took in more than 17,000 displaced Gazans, many of them children, after Saturday's warnings by Israel that civilians must clear out of northern Gaza.

Members of the Attar clan took over part of the second floor, with more than 40 people sleeping in each classroom. Mariam, Sada, Omar and the children were squeezed into one half of a room, their space demarcated by benches. Another family from the clan stayed in the other half of the room. A blanket draped across an open doorway offered the only measure of privacy.

In the classroom, the scene was chaotic, with children pushing and shoving each other and mothers yelling at them to behave. There was nothing to do for children or grown-ups, except to wait.

Mariam Attar, 35, said they spent the night on the hard floor for lack of mattresses.

She sat on the floor, her back leaning against a wall, and held her youngest, 16-month-old Mahmoud. She said her older children have become clingy, some asking that she accompany them to the communal toilet.

Recalling the latest bombings, she said: "We felt the house was going to fall on top of us and so the children started to scream. I was screaming and my husband was screaming."

Her 14-year-old son Mohammed said the family cowered on the ground in the living room during the bombing to avoid being hit by shrapnel. He said the time passed slowly because they had no electricity or TV.

Mohammed and Ahmed, who is from another branch of the clan, said they and other children often play "Arabs and Jews," fighting each other with toy guns or wooden sticks as make-believe weapons. Arabs always win, the boys said.

Rasem Shamiya, a counselor who works for the U.N. school system, said many of the children show signs of trauma, including trouble paying attention, aggressive behavior or avoiding contact with others. "They are very stressed," he said. "Since these children were born, they have never known peace."

Sada Attar, 43, said she worries her children and others in that generation will come to see violence as normal.

"These disturbed children are not going to be good for Israel's long term interests," she said. "The child will naturally rise up and confront the Zionist enemy with the stone, with fire, with everything in their power."

Shortly after she spoke, the children got a brief break from the chaos. Volunteers showed up in the school courtyard, carrying crayons, paper, hula hoops and soccer balls. Ahmed and other boys started kicking a ball around and he quickly became engrossed in the game.

Israeli children, especially in the areas close to Gaza, have also been affected. Since 2000, Gaza militants have fired thousands of rockets at Israeli communities. Psychologists have found high rates of anxiety and bed-wetting among children in the border town of Sderot.

During the current bout, Israeli mothers were seen shielding their children with their bodies as sirens warned of incoming rockets. Other footage showed children weeping and cowering in fear as explosions were heard near their homes.

Several Israeli children were hurt by rockets, including 11- and 12-year-old sisters playing outside and a 16-year-old boy who was seriously hurt by shrapnel as he returned from a barber.

In Gaza, about one-fourth of the over 190 Palestinians killed in the past week were children, according to U.N. figures.

The children's fears are very real and parents in Gaza are increasingly unable to reassure them, said Pierre Krahenbuhl, who heads the U.N. agency that provides aid to Palestinian refugees.

"Today, we met with families who shared with us that they have simply no more answers to give when the children ask them why are the homes shaking, why is there so much destruction," he said.

On Tuesday, some of the displaced, including Mariam, Sada and their children, left the school and returned home, apparently encouraged by Egypt's call for a cease-fire that was to take effect later in the day.

However, the hoped-for lull only lasted a few hours. By Tuesday afternoon, Gaza militants had fired about three dozen rockets at Israel and Israel resumed air strikes on targets in Gaza.

Some members of the Attar clan chose to remain at the school despite faint hopes for a cease-fire. "I want to go home, but I am still afraid," said 42-year-old Mohammed Attar, a relative of the sisters.


Associated Press writer Ian Deitch in Jerusalem contributed to this report.