Israeli forces have stepped up their offensive in Gaza.
Over 340 people have been killed since the fighting began two weeks ago.
The UN Secretary General Ban Ki-Moon is preparing to arrive in the region later today.
The number of Gaza residents seeking shelter in UN buildings has gone beyond 50,000.
US President Barack Obama has backed Israel's right to self-defence, but warned against escalation in Gaza.
Speaking to Prime Minister Benjamin Netanyahu on Friday, he underlined his support for Israel's right to defend itself against Palestinian militants.
But he said he was "deeply concerned" about civilian losses.
Israel's permanent representative at the UN - Ron Prosor - has told its Security Council it didn't launch the operation out of choice.
Thousands of anti-war protesters staged a demonstration in Dublin, calling for an end to the assault on Gaza.
Meanwhile Sinn Féin Leader Gerry Adams has called for the expulsion of the Israeli Ambassador.
Deputy Adams said it's time for a diplomatic offensive by the Irish Government, to encourage the government of Israel to end its military onslaught against the civilian population in the Gaza Strip.
He also wants the Government to push for the immediate suspension of the EU's preferential trade agreements with Israel.
