"More than 700 people have been killed in Israel, while more than 400 Palestinians have been killed, according to authorities. Some 2,300 others have been wounded in Gaza, with power cuts threatening lives of hundreds of injured and patients,"  the Palestinian Ministry of Health in Gaza was quoted as saying by CNN.

Israel has declared war on Hamas and initiated airstrikes in response to their fierce attack.

The Israel Defense Forces told CNN that  Israel has "severely degraded the capabilities" of the Palestinian militant group Hamas as airstrikes on Gaza continued into early Monday.

Israel Defense Forces said 2150 people have been injured in the attack so far.

Meanwhile, top UN officials engaged key actors amid the spiraling Israeli-Palestinian conflict while UN peacekeepers detected rocket and artillery fire exchanged across the Israel-Lebanon border ahead of Sunday’s Security Council emergency closed-door meeting on the unfolding crisis.

The UN agency is currently sheltering 73,538 internally displaced people in 64 of its schools in all areas in the Gaza Strip.

An UNRWA school sheltering 225 people was "directly hit" and severely damaged, but no casualties were recorded, the agency said. 

New reports emerged of alarming food scarcity and clashes across the Israel-Lebanon border.

The UN chief of the Middle East Peace Process, Tor Wennesland, “is in close contact” with the United States, European Union, Qatar, Egypt, and Lebanon “to discuss the ongoing war” in Israel and Gaza, according to a social media post by his office, UNSCO.

“Priority now is to avoid further loss of civilian life and deliver much needed humanitarian aid to the Strip,” the UNSCO post said, adding that the “UN remains actively engaged to advance these efforts”.

Calls to protect civilians

Top UN officials have called for an immediate cessation of violence.

UN Secretary-General António Guterres earlier condemned “in the strongest terms” the attack by Hamas against Israeli towns, UN Spokesperson Stéphane Dujarric said, urging “maximum restraint” and that “all diplomatic efforts” are made “to avoid a wider conflagration”.

“Civilians must be respected and protected in accordance with international humanitarian law at all times,” the UN chief said in a statement.

As the conflict intensifies, civilians, including vulnerable children and families, face mounting challenges in accessing essential food supplies, with distribution networks disrupted and production severely hampered by hostilities, according to the World Food Programme (WFP).

“WFP urges safe and unimpeded humanitarian access to affected areas, calling on all parties to uphold the principles of humanitarian law, taking every necessary measure to safeguard the lives and well-being of civilians, including ensuring access to food,” the agency said.

From Gaza, UNRWA reported that food operations remain on hold until further notice, with 14 distribution centres now closed. Some 112,759 families, or 541,640 individuals, had not yet received food assistance, the agency said.