Gaza City, October 21 (RHC)-- Israel has killed at least 640 Palestinians in north Gaza since it laid siege to the area 17 days ago, 33 of them since dawn on Monday, medical sources have told Al Jazeera.

“Genocide is unfolding in northern Gaza in its clearest form, in full view of the world,” the Palestinian Authority’s Foreign Ministry warned in a statement on Sunday.

“The occupation army is forcing residents of northern Gaza to either flee under bombardment or face killing in what resembles a circle of certain death,” it said, adding that the failure of the international community to stop this “war of extermination has emboldened Israel to continue its deadly campaign”.

Reporting from Deir el-Balah in central Gaza, Al Jazeera’s Tarez Abu Azzoum said civilians in northern Gaza are “trapped” in their houses amid “a mass blackout”.

“Food, water, and medicine have run out,” he added. While Israeli air attacks have hit several areas across Gaza, the concentration of its army attacks remains in the north, particularly Jabalia refugee camp, Abu Azzoum said.

Meanwhile, Palestinian women forced to flee north Gaza said the Israeli army is separating and arresting dozens of men at checkpoints.

Abu Azzoum said rescue workers recovered the bodies of five Palestinians killed in the southern Rafah City. At least 18 others were killed and several people injured in an Israeli shelling in Jabalia, medical sources told Al Jazeera. Two Palestinians were also killed in north Gaza’s as-Saftawi area northwest of Gaza City.

Reporting from Al-Ahli Hospital in Gaza City, where Palestinian casualties from the north have been arriving after a series of attacks, Ibrahim al-Khalili described “an unimaginable situation” with funerals held since the early morning.

“People filling water containers were targeted and killed.  In Beit Lahiya, a school shelter was also attacked with several killed and dozens wounded,” al-Khalili said.

In a statement, the UN Human Rights Office said Israeli forces demolished a block of homes in Jabalia on Monday, while also hitting at least three UNRWA schools there.

Israel “may be causing the destruction of the Palestinian population in Gaza’s northernmost governorate through death and displacement”, amid continuous bombardment across the besieged enclave, the UN body said.

Israel’s brutal onslaught on the Gaza Strip has killed more than 42,600 people, mostly women and children, and wounded 99,800 others since October last year – although the numbers are likely to be far higher with thousands of victims buried underneath the rubble.

Despite Israel claiming to have defeated Hamas in northern Gaza and Jabalia in early January this year, it launched yet another offensive there in what the UN and Palestinian rights groups now fear is an effort to empty it of Palestinian residents.

Humanitarian workers and health authorities in Gaza say most aid has not reached northern Gaza due to heavy Israeli bombardment.

Sam Rose, director of planning at the UN agency for Palestinian refugees, said people in Gaza “are facing absolutely unimaginable conditions.”   They have been going through “12 months of war, repeated displacement, bombardment, loss of life, loss of property, deprivation and lack of food and water”, he told Al Jazeera from Khan Younis in southern Gaza.

“What we have seen over the past two weeks has taken it to another level in terms of the intensity of the bombardment and military operations,” Rose said.

“It is very difficult to get a precise read on what is going on due to the closure and the way the area is strangled, but every report we are getting suggests the situation up there for the approximately 175,000 people we estimate remaining is beyond catastrophic.”

Al Jazeera’s Hind Khoudary, reporting from Deir el-Balah, said Israeli forces are “invading homes, forcibly evicting residents”. “People are crying out for help,” she said.

“[They] feel unheard despite their efforts to share their experiences online. They record videos, yet they remain trapped. With no food, no aid, and no support reaching them, they continue to suffer as the relentless Israeli air attacks persist,” she added.