It is Israel's responsibility - as the occupying power in the Gaza Strip - to restore public order and safety in the Palestinian territory so humanitarian aid can be delivered, the United Nations said on Friday.

U.N. Secretary-General Antonio Guterres said there is as "total lawlessness" in Gaza, where the U.N. has warned a famine looms for the population of 2.3 million after more than eight months of war between Israel and Palestinian militants Hamas.

"Most of the trucks with humanitarian aid inside Gaza are now looted," Guterres told reporters on Friday, adding that Israel prevented the U.N. from using Palestinian civil police for aid security. "There is total chaos in Gaza and there is no authority in most of the territory."

Israel's military announced on Sunday that there would be a daily daytime pause in its attacks along a key road in southern Gaza that the U.N. and aid groups use to access the Kerem Shalom crossing from Israel.

But U.N. spokesperson Farhan Haq said on Friday that along with fighting between Israel and Hamas, the risk of crime had "effectively prevented humanitarian access" to critical areas, including Kerem Shalom.

"As the occupying power, it is incumbent upon the Israeli authorities to restore public order and safety as far as possible and facilitate safe humanitarian access so that assistance reaches civilians in need," Haq said.

Hamas came to power in Gaza in 2006 after Israeli soldiers and settlers withdrew in 2005, but the enclave is still deemed as Israeli-occupied territory by the United Nations. Israel controls access to Gaza.

"We see extreme difficulty in distributing inside Gaza," Guterres said. "There must be a mechanism guaranteeing that there is a minimum of law and order that allows for that distribution to take place"

"That is why a ceasefire is so necessary to get properly organized and implement a plan for that purpose," he said.