An Israeli attack on a school in Gaza run by the UN agency for Palestinian refugees has killed more than 40 people and wounded over a hundred.

Tuesday's attack caused the single highest death toll since the beginning of Israel's offensive on December 27th.

Israel's Prime Minister said he hoped to end the offensive soon, but not before certain conditions are met.

Reports say artillery shells from Israeli tanks exploded about 10 meters outside a UN school in the Jabalia refugee camp in northern Gaza on Tuesday evening.

Palestinian officials say 46 bodies have been recovered, with 150 others wounded.

The Israeli army said its soldiers came under fire from militants hiding in the school, and responded defensively.

It was the second deadly Israeli attack to strike a UN school since the ground invasion of Gaza began.

On Monday evening, three Palestinians were killed at another UN school outside Gaza City.

In both cases, the schools had been used as shelters for people displaced by the violence.

Meanwhile, Israeli forces edged closer to Gaza's major population centers on Tuesday, hitting new targets.