The UN`s humanitarian chief has told the BBC the situation in Gaza after a three-week Israeli offensive against Hamas was worse than he anticipated.
Sir John Holmes, who visited Gaza on Thursday, said he was shocked by "the systematic nature of the destruction."
He said that the territory`s economic activity had been set back by years.
The International Committee of the Red Cross (ICRC) President Jakob Kellenberger said conditions in Gazan hospitals were the worst he had seen.
UN workers have been given access to Gaza. On Friday, Israel lifted a ban on international aid agencies entering the Palestinian territory.
The ban had been in place since early November when tensions mounted between Israel and Hamas.
Staff from a number of international nongovernmental organisations (NGOs) were allowed to cross into Gaza on Friday morning.
Michael Bailey from Oxfam said: "We are extremely relieved to be able to join our local colleagues inside Gaza and to be able to provide them with some support and relief from th