"From different doctors, particularly in the maternity hospitals, they're reporting that they're seeing a big rise in children born with low birth weight, and just not surviving the neonatal period because they're born too small," WHO spokeswoman Margaret Harris said at a briefing in Geneva.
The WHO is unable to establish precise statistics on child mortality because of the devastation in the Palestinian territory after six months of war between Israel and Hamas, with Ms Harris saying many people do not even get to hospital. "If you have got an underlying condition, malnutrition will kill you much more quickly, so they become the most urgent patients," she said.
Israeli authorities said its forces had battled Palestinian militants inside the complex, killing at least 200 and recovering stockpiles of weapons, explosives and cash.