Israel-Gaza updates: IDF says 3,500 'terror targets' hammered in 10 days

Israeli soldiers are fighting for the first time in the heart of Khan Yunis, a city in southern Gaza, the Israel Defense Forces said.

"The city of Khan Yunis is a terrorist stronghold," the IDF said. "The entire leadership of the Hamas terrorist organization -- both military and political -- proliferated in the area of Khan Yunis."

Israeli troops have eliminated terrorists and their infrastructure in the area, the IDF said. One strike was on a mosque that the IDF said was being used to store weapons.

Another hospital in Gaza, Kamal Adwan Hospital in northern Gaza, is on the verge of closing, with only 20 patients currently getting care, according to Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization.

"This is due to intense fighting as well as a lack of basic supplies: water, food, medicines and fuel," he wrote Wednesday on X, the social media platform formerly known as Twitter.

Nineteen hospitals in Gaza are nonfunctioning, he said. Gaza now has two field hospitals, 14 partially functioning hospitals and three minimally functioning hospitals, Tedros said.

United Nations Secretary-General António Guterres said Wednesday that he's invoked Article 99 of the U.N. Charter for the first time in his six years as leader.

Article 99 says that the secretary-general "may bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security."

"Facing a severe risk of collapse of the humanitarian system in Gaza, I urge the Council to help avert a humanitarian catastrophe & appeal for a humanitarian cease-fire to be declared," Guterres said in a post on X.

In a letter to the U.N. Security Council president, Guterres said, "The situation is fast deteriorating into a catastrophe with potentially irreversible implications for Palestinians as a whole and for peace and security in the region. … The international community has a responsibility to use all its influence to prevent further escalation and end this crisis."

Israeli forces are now "encircling" the house belonging to Yahya Sinwar, the leader of Hamas in the Gaza Strip, Israeli Prime Minister Benjamin Netanyahu said.

"It's only a matter of time until we catch him," Netanyahu said.

The prime minister also said Israel is exerting pressure to allow Red Cross workers to visit the more than 100 hostages still being held by Hamas.

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UN says there is no safe zones in Gaza as Israeli strike continues

ABC News foreign correspondent James Longman reports from Israel as the military ramps up strikes on Gaza.

ABCNews.com