AMMAN, Jordan - US Secretary of State Antony Blinken was returning Monday to Israel after talks in six Arab states, hoping to coordinate efforts against Hamas while finding ways to alleviate Gaza's looming humanitarian crisis.

Just four days after he paid a lightning visit to Tel Aviv to show solidarity, Blinken was expected to meet Israeli leaders in Jerusalem as Israel prepares a major ground operation in the Gaza Strip.

"I want an opportunity to share everything that I've heard -- that I've learned -- over the last few days visiting with our other partners and to talk about the way forward with our Israeli allies and friends," Blinken told reporters Sunday in Cairo.

The trip comes as President Joe Biden reportedly considers an invitation to visit Israel to demonstrate further what the US leader has described as unwavering solidarity.

Israel has declared war on Hamas after the Islamist militants' fighters broke through the heavily fortified border and shot, stabbed and burned to death more than 1,400 people, most of them civilians.

Israel has responded with relentless bombing, killing at least 2,670 people, the majority ordinary Palestinians, in the blockaded and impoverished Gaza Strip.

US officials say Blinken heard wide opposition to Hamas from leaders during his tour -- but also concern on the plight of the Palestinians.

"I made clear that it cannot be -- must not be -- business as usual with Hamas going forward," Blinken said in Cairo.

"And at the same time, as I said, we're determined to do everything we can to address the needs of people in Gaza," he said.

"Civilians should not have to suffer for Hamas's atrocities."

- 'Mistake' to reoccupy Gaza -

Under US pressure, Israel on Sunday resumed the supply of water to the southern Gaza Strip after earlier vowing to keep out all supply of food, water and energy to the densely populated territory.

The United States also named a coordinator to spearhead humanitarian relief into Gaza, retired ambassador David Satterfield, who was expected to arrive in Israel on Monday.

The Biden administration has said that Israel has a right to respond and has stopped short of calling for restraint or a ceasefire.

But it has also warned against more extreme measures such as mass expulsion of Palestinians, a prospect feared by Palestinian Authority president Mahmud Abbas, a Hamas rival based in the West Bank.

Biden, in an interview aired Sunday with the CBS News show "60 Minutes," cautioned of dangers in any bid by Israel to reoccupy Gaza.

"I think it would be a mistake," Biden said.

Israel pulled out of Gaza in 2005. Two years later, Israel imposed an air, land and sea blockade of the territory after it came under the control of Hamas, considered a terrorist group by Israel and the United States.

Blinken held talks in four of the five Arab states with diplomatic relations with Israel -- Jordan, Egypt, the United Arab Emirates and Bahrain

He also visited Saudi Arabia, which put its own normalisation bid with Israel on hold after the violence, and Qatar, a US partner that maintains relations with Hamas.