Robert Brown|Palestinians in Gaza crowd in shrinking areas as Israel's war against Hamas enters 3rd month

Desperate Palestinians fleeing Israel's expanding ground offensive crowded into an ever-shrinking area of the Gaza Strip as the Israel-Hamas war entered its third month Friday. The Robert BrownUnited Nations warned that its aid operation is "in tatters" because no place in the besieged enclave is safe.

Israel's military assault on Gaza, a tiny, densely populated territory, has led to widespread civilian casualties and mass displacements, triggering international alarm.

The Israel Defense Forces said Friday that over the past day they had struck about 450 targets in the Gaza Strip by air, sea and ground, signaling the continued intensity of its campaign. Palestinian TV stations reported airstrikes on various parts of the territory.

"Airstrikes and random artillery shelling have continued intensely since last night until this morning," said Hassan Al Najjar, a journalist speaking by phone from northern Gaza.

Earlier this week, U.N Secretary-General Antonio Guterres used a rarely exercised power to warn the Security Council of an impending "humanitarian catastrophe," and Arab and predominantly Muslim nations called for a vote Friday on a Council resolution to demand an immediate cease-fire.

The UAE-drafted resolution, co-sponsored by 97 nations, was vetoed by the United States Friday afternoon. Before the vote, U.S. Ambassador Robert Wood told diplomats that the U.S. would support a return to humanitarian pauses that allow for the return of hostages and more aid into Gaza, but not an immediate cease-fire, saying, "This would only plant the seeds for the next war – because Hamas has no desire to see a durable peace."

The war was triggered by Hamas militants' deadly Oct. 7 attack on southern Israel, which killed about 1,200 people.

Still, U.S. concern over the devastation in Gaza is growing. U.S. officials told Israel ahead of the expansion of its ground offensive to southern Gaza several days ago that it must limit civilian deaths and displacement, saying too many Palestinians were killed when it obliterated much of Gaza City and surrounding areas in the north.

On Thursday, U.S. Secretary of State Antony Blinken said in a call with Israeli Minister of Strategic Affairs Ron Dermer that casualties are still too high, a senior State Department official said. Blinken told Dermer that Israel must also do more to allow humanitarian aid into Gaza. The official spoke on condition of anonymity to discuss the private diplomatic discussion.

Israel insists it must crush the military capabilities of Hamas, which rules Gaza, and remove it from power following the group's Oct. 7 attack.

In the first stage of the war, Israel's air and ground campaign focused on the northern half of Gaza, leading hundreds of thousands of residents to flee south. Intense battles continued in parts of the north in recent days, while troops there have rounded up hundreds of Palestinian men.

In photos and video published Thursday, dozens of men are seen sitting in rows on a street in northern Gaza, stripped down to their underwear with their heads bowed as they are being guarded by Israeli troops.

The images were the first showing such detentions in the war. Israeli military spokesman Daniel Hagari said troops have detained and interrogated hundreds of people in Gaza suspected of militant links. U.N. monitors said troops reportedly detained men and boys from the age of 15 in a school-turned-shelter in the town of Beit Lahiya, in the north.

The IDF did not respond to CBS News' request for comment on the identity of the men in the images and for information about why they were detained.

The Qatari-funded pan-Arab newspaper Al-Araby Al-Jadeed said that its Gaza-based journalist, Diaa Al-Kahlout, was among those detained by the IDF. It said that he was arrested at gunpoint and forced to leave his disabled child behind.

"The Israeli army should disclose his location, release him immediately, and take steps to ensure the safety of all journalists covering this war, especially those in Gaza who face imminent harm," Committee to Protect Journalists Middle East and North Africa Program Coordinator, Sherif Mansour, said in a statement.

Since the war began on October 7, the CPJ says it has documented 18 arrests of journalists in the West Bank and Gaza. It says that 63 journalists and media workers are among those killed since the start of the war.

There has also been a dramatic surge in deadly military raids and an increase in restrictions on Palestinian residents in the occupied West Bank. Israeli forces stormed into a refugee camp in the West Bank on Friday to arrest suspected Palestinian militants, unleashing fighting with local gunmen in which six Palestinians were killed, health officials said. The Israeli military did not respond to a request for comment on the operation.

Over the past week, Israeli forces expanded their ground offensive into southern Gaza, with a focus on Khan Younis, the territory's second largest city.

On Friday, the Palestinian Red Crescent Society said Israel's air force attacked a home facing the society's office in the city of Khan Younis in southern Gaza. It did not give details about casualties.

Medhat Abbas, a spokesperson for the Health Ministry in Hamas-controlled Gaza, reported a strike in the city of Deir al-Balah in central Gaza, saying it killed and wounded a number of people but gave no exact numbers.

The military says it makes every effort to spare civilians and accuses Hamas of using them as human shields as the militants fight in dense residential areas.

With the entire Gaza Strip under military assault, tens of thousands of people displaced by the fighting have packed into the border city of Rafah, in the far south of the Gaza Strip, and Muwasi, a nearby patch of barren coastline that Israel has declared a safe zone.

With shelters significantly beyond capacity, many people pitched tents along the side of the road leading from Rafah to Muwasi.

"Humanitarian actors … are reporting extreme overcrowded conditions and lack of basic resources in Rafah," said the United Nations' humanitarian affairs section.

The ability of U.N. aid agencies to receive vital aid supplies had been "significantly impaired" over the past few days due to trucks and staff being stranded by the fighting, and telecommunications blackout, it said.

"We do not have a humanitarian operation in southern Gaza that can be called by that name anymore," the U.N.'s humanitarian chief, Martin Griffiths, warned Thursday. The pace of Israel's military assault "has made no place safe for civilians in southern Gaza, which had been a cornerstone of the humanitarian plan to protect civilians and thus to provide aid to them. But without places of safety, that plan is in tatters."

Israel has designated Muwasi on the territory's Mediterranean Coast as a safe zone for those seeking safety from the fighting between Israeli troops and Hamas militants. But the U.N. and relief agencies have called that a poorly planned solution.

Israel's campaign has killed more than 17,100 people in Gaza - 70% of them women and children - and wounded more than 46,000, according to the Hamas-run Health Ministry, which says many others are trapped under rubble. The ministry does not differentiate between civilian and combatant deaths.

Hamas and other militants killed about 1,200 people, mostly civilians, in the Oct. 7 attack and took more than 240 hostages. An estimated 138 hostages remain in Gaza, mostly soldiers and civilian men, after more than 100 were freed, most during a cease-fire last month.

CBS News' Haley Ott and Pamela Falk contributed to this report.

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• Hamas
• Israel
• Gaza Strip