A wounded Palestinian child sits on the floor of Nasser hospital following Israeli strikes [Source: Reuters]

Israel sharply increased strikes on the Gaza Strip, pounding the length of the Palestinian enclave and killing hundreds in a new, expanded phase of the war, as the U.S. again signalled that Israel could do more to protect civilians in the enclave.

The Israeli military 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”, U.N. Secretary-General Antonio Guterres declared that nowhere in Gaza was safe for civilians, hours before the U.S. 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.

In Washington, the White House on Friday said more could be done by Israel to reduce civilian casualties and the U.S. shared international concerns about the humanitarian situation in Gaza.

On Thursday, U.S. Secretary of State Antony Blinken said in Washington that Israel needed to take steps to protect Gaza’s civilian population. “And there does remain a gap between…the intent to protect civilians and the actual results that we’re seeing on the ground,” he told a press conference.

With most Gazans now displaced and unable to access any aid, hospitals overrun and food running out, the main U.N. 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 1,200 people and took 1,200 more than 240 hostages.

An Israeli commander, Brig. Gen. Dan Goldfuss, said in a video message recorded in Khan Younis that his forces were fighting house to house and “shaft to shaft”, a reference to tunnel shafts. As he spoke, gunshots rang out in the background.