"What Israeli forces are doing in besieged North Gaza cannot be allowed to continue," Msuya said.
"Instead of receiving aid, we are receiving tanks."
In particular, Msuya emphasized Israel's targeting of hospitals and shelters and interference with relief work.
"Hospitals have been hit, and health workers have been detained. Shelters have been emptied and burned down. First responders have been prevented from saving people from under the rubble. Families have been separated, and men and boys are being taken away by the truckload," she said.
Msuya estimated that Israel's actions in the north had killed hundreds and displaced tens of thousands. According toAl Jazeera, an Israeli siege on the north that began earlier in October has killed around 640.
"The entire population of North Gaza is at risk of dying," Msuya said. "Such blatant disregard for basic humanity and for the laws of war must stop."
The U.N. official's remarks came as Israeli troops withdrew from a deadly attack on Kamal Adwan Hospital in Beit Lahia, which Al Jazeera correspondent Tareq Abu Azzoum said "is considered a medical lifeline for the two-thirds of Palestinians in northern Gaza."
The Israel Defense Forces (IDF) had surrounded the hospital for days before entering and opening fire on Thursday and Friday, the Gaza Health Ministry and the hospital's director toldCNN.
"Instead of receiving aid, we are receiving tanks," hospital director Dr. Hussam Abu Safiya said in a video.
Medics told Al Jazeera that the IDF had detained 44 members of the hospital team, later releasing 14 of them. The director of field hospitals in Gaza, Marwan Al-Hams, said that soldiers had also destroyed medications as they left, "preventing us from saving the wounded."
"It is a catastrophic situation as patients and the wounded are left on the floor without any medical attention," hospital spokesperson Hisham Sakani told Al Jazeera. "We are facing grave dangers, and here I am once again sending an SOS to the whole world. We pray to God almighty our plight comes to an end and Israeli massacres [are] ceased."
"The entire population north of Gaza Strip are now without any medical service after all the hospitals have been destroyed and forced out of operation," Sahani continued.
Msuya's statement also came a day after U.N. High Commissioner for Human Rights Volker Türk called Friday's attacks on northern Gaza the "darkest moment" of the war.
"The Israeli Government's policies and practices in northern Gaza risk emptying the area of all Palestinians," Türk said. "We are facing what could amount to atrocity crimes, including potentially extending to crimes against humanity."
Msuya and Türk's statements reflect the opinion of human rights experts that Israel is committing genocide in Gaza. The International Court of Justice is still considering the genocide case brought by South Africa against Israel. To date, the Israeli assault has killed at least 42,924 people and wounded 100,833, but the true numbers could be much higher.
Emergency medical doctor Mads Gilbert, who has volunteered in both Gaza and Lebanon, criticized Western governments for allowing the raid on Kamal Adwan, as well as Israel's systematic attacks on healthcare workers and facilities in Gaza.
"We need an additional factor to understand why this has been allowed to go on, and that is actually that the Palestinian people are defined as under-humans," Gilbert told Al Jazeera. "We would never have allowed this to happen, for example, in Ukraine. Almost 250,000 people in the northern part of Gaza have now no healthcare, and that in itself is part of the genocide."
The Institute for Middle East Understanding called on both the international community and the U.S. government to respond to Israel's violations of international law.
"The Biden-Harris administration must stop the flow of U.S. weapons to Israel which constitutes a necessary step to halting Israel's ongoing war crimes," IMEU wrote on social media Saturday. "It's time for an arms embargo now."
