US Secretary of State John Kerry has said a ceasefire between Israel and Gaza needs to be restored as soon as possible, as he expressed his concern for civilians' safety.
Palestinian officials say more than 240 people have already died in air strikes, including 14 children under 12 while one Israeli has also died.
Israeli forces have launched a ground offensive in a bid to destroy tunnels that run under the Gaza border into Israel.
During a conversation with Israeli prime minister Benjamin Netanyahu, Mr Kerry "reaffirmed" America's support for Israel's "right to defend itself against terrorist threats" but said it must do everything possible to reduce civilian casualties.
"The Secretary emphasised the need to avoid further escalation and to restore the 2012 cease-fire as soon as possible," a White House statement said.
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.