Israel must protect innocent Gaza residents by distinguishing between Hamas militants and civilians, the White House warned Sunday, as world leaders stepped up calls for desperately needed humanitarian aid to reach the war-torn Palestinian territory.

Israel has intensified its air and ground operations against Hamas in Gaza following a bloody attack by the Palestinian militant group more than three weeks ago that Israeli authorities say killed at least 1,400 people, mostly civilians.

Since the 7 October attack, more than 8,000 Palestinians have been killed by Israel's relentless retaliatory bombardments, half of them children, says the health ministry in the Hamas-run Gaza Strip.

The United Nations warned Sunday that the "civil order" was starting to collapse in Gaza after thousands of people ransacked its food warehouses there, taking wheat, flour, and other supplies. 

The bloodshed saw the Biden administration warn Israel on Sunday that it must protect civilian lives. 

While the US ally has the right to defend itself, it must do so "in a manner consistent with international humanitarian law that prioritizes the protection of civilians," Biden told Israeli Prime Minister Benjamin Netanyahu in a phone call, the White House said. 

He spoke after his national security adviser, Jake Sullivan, told CNN that Israel "should be taking every possible means available to them to distinguish between Hamas — terrorists, who are legitimate military targets — and civilians, who are not." 

Biden also spoke with Egyptian President Abdel Fattah al-Sisi, and the two leaders "committed to the significant acceleration and increase of assistance flowing into Gaza beginning today," according to a readout from the White House.

That announcement came as other world leaders also issued urgent calls for aid to Gaza. 

Britain's Prime Minister Rishi Sunak and French President Emmanuel Macron "stressed the importance of getting urgent humanitarian support" into the Palestinian territory, while UN chief Antonio Guterres said the situation was getting "more desperate by the hour."

Sunak and Macron spoke by telephone and "agreed to work together on efforts both to get crucial food, fuel, water, and medicine to those who need it and to get foreign nationals out," said a Downing Street spokesperson.

On social media, Macron reiterated a call for a humanitarian truce.

"17 tons of humanitarian freight have arrived in Egypt from France. We are continuing our efforts by air and sea… alongside Egypt and the Red Crescent," he said.

Earlier, Guterres said he regretted that "instead of a critically needed humanitarian pause, supported by the international community, Israel has intensified its military operations."

"The world is witnessing a humanitarian catastrophe," Guterres added on a visit to Nepal's capital Kathmandu. "I urge all those with responsibility to step back from the brink."

Though the United States remains Israel's strongest ally, the Biden administration has insisted that Israeli leaders alone decide its military operations and publicly multiplied appeals to spare the lives of Palestinian civilians. 

The White House also revealed Sunday that it had "worked on" bids to turn communications in Gaza back on. 

Communication had been cut off after Israel slashed internet lines ahead of the intensification of its operations, sparking alarm — although connectivity was gradually returning on Sunday.

The restoration of communications was "critical," the official White House account posted on X, formerly Twitter.

"Aid workers, civilians, and journalists need to be able to communicate to each other and the rest of the world. Our Administration cared about this, worked on it, and are glad to see it restored," the post continued. 

Sullivan, speaking on ABC's "This Week" as he made a round of Sunday talk shows, slammed Hamas's own treatment of civilians, calling them a "brutal terrorist organization" that is "hiding behind the civilian population."

"But it doesn't lessen their (Israel's) responsibility under international humanitarian law and the laws of war to do all in their power to protect the civilian population," he said.

Sullivan also said that US officials are working to help secure the release of more than 220 hostages being held in Gaza by Hamas, as well as to help the hundreds of Palestinian Americans stuck in Gaza.