WASHINGTON

UN Secretary-General Antonio Guterres said Monday that he is "deeply distressed" by Israel's decision to impose a "complete siege" on the Gaza Strip.

Guterres said Defense Minister Yoav Gallant's announcement that Israel will halt all supplies of electricity, food and fuel will only exacerbate what was already a dire humanitarian situation in the coastal Palestinian territory.

"The humanitarian situation in Gaza was extremely dire before these hostilities; now it will only deteriorate exponentially," Guterres told reporters at the UN's New York City headquarters. "Medical equipment, food, fuel and other humanitarian supplies are desperately needed, along with access for humanitarian personnel."

The UN chief emphasized that the latest bout of violence "does not come in a vacuum," and instead "grows out of a long-standing conflict, with a 56-year long occupation and no political end in sight."

"Israel must see its legitimate needs for security materialized – and Palestinians must see a clear perspective for the establishment of their own state realized," Guterres said.

"Only a negotiated peace that fulfills the legitimate national aspirations of Palestinians and Israelis, together with their security alike – the long-held vision of a two-state solution, in line with United Nations resolutions, international law and previous agreements – can bring long-term stability to the people of this land and the wider Middle East region," he added.

Hamas launched Operation Al-Aqsa Flood against Israel early Saturday, firing a barrage of rockets and infiltrating Israel by land, air and sea. It said the surprise attack was in response to the storming of Al-Aqsa Mosque in occupied East Jerusalem, and increased settler violence against Palestinians.

In retaliation, the Israeli military launched Operation Swords of Iron against Hamas in the Gaza Strip, killing at least 560 Palestinians and wounding at least 2,900 others.

At least 800 Israelis have been killed, and over 2,300 others wounded in the fighting, according to the Israeli Health Ministry.

The Interior Ministry in Gaza said the Israeli army has "intensified its aggression" on Gaza with hundreds of raids. The Israeli army said it had struck over 500 targets in overnight raids on Gaza, which they claimed were targets belonging to the Hamas and Islamic Jihad.