Israel shells near UN school, killing at least 30

GAZA CITY, Gaza – Israeli mortar shells struck outside a U.N. school where hundreds of Palestinians had sought refuge on Tuesday, killing at least 30 people — many of them children whose parents wailed in grief at a hospital filled with dead and wounded.

The Israeli army said its soldiers came under fire from militants hiding in the school and responded. It accused Gaza's Hamas rulers of "cynically" using civilians as human shields.

Despite international criticism over civilian deaths and diplomatic push to broker a cease-fire, Israeli said it would push on with the offensive against Hamas.

Israeli ground forces edged closer to two major Gaza towns, and a total of 58 Palestinians were killed Tuesday — with just two confirmed as militants, health officials in Gaza said. A top U.N. official called for an investigation into the mounting civilian death toll.

Past Israeli ground offensives have been cut short when an errant shell or missile hit a civilian center, leading to international outcries that forced Israel to stand down.

The explosions marked the second time in hours a U.N. school came under attack.

It was the deadliest assault since Israel sent ground forces into Gaza last weekend as part of a larger offensive against the ruling Hamas militant group that has killed nearly 600 Palestinians. Nearly half of the dead are civilians, according to U.N. and Palestinian officials.

"There's nowhere safe in Gaza. Everyone here is terrorized and traumatized," John Ging, the top U.N. official in Gaza, said after the first strike on the compound of a U.N. school killed three people in a courtyard. The school has served as a shelter for Gaza City refugees fleeing the blistering 11-day offensive.

A Palestinian rocket — one of two dozen fired from Gaza on Tuesday — wounded an Israeli infant.