The Israeli military on Friday said it had struck more than 450 targets in Gaza from land, sea and air over the past 24 hours - the most since a truce with Hamas collapsed last week and about double the daily figures typically reported since.
Decrying a "spiralling humanitarian nightmare", UN Secretary-General Antonio Guterres declared that nowhere in Gaza was safe for civilians, hours before the US vetoed a Security Council demand for a humanitarian ceasefire.
The vote, including 13 members in favour and one abstaining, diplomatically isolated Washington as it shielded ally Israel.
"We are at breaking point," he told the UN Security Council, saying the collapse of the humanitarian system could result in a complete breakdown of public order.
"The people of Gaza are being told to move like human pinballs - ricocheting between ever-smaller slivers of the south, without any of the basics for survival," he said, referring to Israeli instructions to Gazan civilians to move to safe areas.
The United States has vetoed a UN Security Council demand for an immediate humanitarian ceasefire. (EPA PHOTO)
In Washington, the White House on Friday said more could be done by Israel to reduce civilian casualties and the US shared international concerns about the humanitarian situation in Gaza.
With most Gazans now displaced and unable to access any aid, hospitals overrun and food running out, the main UN agency there said society was "on the verge of a full-blown collapse" and its ability to protect people there was "reducing fast".
Residents and the Israeli military both reported intensified fighting in both northern areas, where Israel had previously said its troops had largely completed their tasks last month, and in the south where they mounted a new assault this week.
Gaza's health ministry reported 350 people killed on Thursday, and on Friday it said the death toll from Israel's campaign in Gaza had risen to 17,487, with thousands more missing and presumed buried under rubble.
More strikes were reported on Friday morning in Khan Younis in the south, the Nusseirat camp in the centre and Gaza City in the north.
On Friday evening, residents reported intensified Israeli tank fire on the districts of Shejaia, Nafaq, Sabra and Jala in north Gaza, while health officials said at least 10 people were killed in an air strike on a house in Khan Younis.
Israel's military said 94 Israeli soldiers had been killed fighting in Gaza since its ground invasion of the densely populated, coastal enclave began in late October in retaliation for Hamas' rampage in southern Israel in which it killed 1200 people and took more than 240 hostages.
"The eyes of the world – and the eyes of history – are watching. Time to act." — UN Web TV (@UNWebTV) @antonioguterresWatch Security Council on the situation in the Middle East, including the Palestinian question: https://t.co/XaSTmxOwNxAvailable in: لعربية 中文 English Français Русский Español pic.twitter.com/RGjtKLKrRyDecember 8, 2023
Israel launched what it says is a campaign to destroy Hamas after the Islamist militant group's bloody October 7 cross-border raid.
Since then, most of Gaza's 2.3 million people have been driven from their homes. With fighting now going on across both halves of Gaza, residents say it has become almost impossible to find refuge.
Israel says it is providing detail about which areas are safe and how to reach them, and says Hamas is to blame for harm that befalls civilians because it operates among them, an accusation the Islamist group denies.
Hamas reported the most intense clashes with Israeli forces were taking place in the north in Shejaia, as well as in the south in Khan Younis, where Israeli forces reached the heart of the enclave's second-biggest city on Wednesday.
Israel's military said two of its troops were severely injured in an unsuccessful operation to rescue hostages held in Gaza. It said "numerous terrorists" were killed.
Israel's chief military spokesperson Rear Admiral Daniel Hagari said Israel had detained more than 200 suspects from Gaza in the last 48 hours and that dozens of them were taken to Israel for questioning, adding Hamas commanders were among them.
Hamas' armed wing said it had thwarted an attempt to free a captured Israeli soldier, which it said resulted in his death, and that Israeli bombing over Gaza had resulted in the death and injuries of other Israeli hostages.