A United Nations school sheltering people who have fled Israeli airstrikes in Gaza has been hit by shelling from Israeli shelling, the UN said.
Fighting has now been raging for 16 days and has left more than 650 dead.
The Palestinian president has told US Secretary of State John Kerry that Israel's offensive in Gaza is a "war without justification".
Speaking after meeting Kerry in Ramallah, Mahmoud Abbas accused the Israelis of forging "a war against the Palestinian people".
Mr Kerry said the US would continue to push for a ceasefire in the conflict that has killed at least 687 Palestinians and 32 Israelis.
In between the bandages, I could see the soreness of Randa’s skin. Her eyes stare out at a world which has been brutal to her.
An Israeli student has started an online campaign in an attempt to encourage respect between Jews and Arabs.
A BBC Arabic reporter was set upon by an angry Israeli bystander in the middle of a live broadcast on the situation in Gaza.