US President Joe Biden told Israeli Prime Minister Benjamin Netanyahu Thursday it was "critical" to protect civilians in Gaza and said much more aid must be allowed in, the White House said.

Biden, who was speaking by telephone to Netanyahu for the first time since November 26, called for the creation of humanitarian corridors to "separate the civilian population from Hamas".

"The president emphasized the critical need to protect civilians and to separate the civilian population from Hamas including through corridors that allow people to move safely from defined areas of hostilities," the White House said in a statement.

The United States has strongly defended Israel's right to defend itself after the October 7 attacks by Hamas, in which Israel says 1,200 people were killed while 138 people remain as hostages.

But the Biden administration says that too many Palestinian civilians are dying in Israel's attacks. The Hamas-run health ministry said the death toll had risen to 17,177 by Thursday.

It has also told Israel, which is now attacking southern Gaza following the breakdown of a shortlived truce last week, that numbers of casualties and displacements should not be as great as during its initial assault on the north.

As heavy urban combat raged in and around Gaza's biggest cities on Thursday, US Secretary of State Antony Blinken said Israel needed to do more.

"It remains imperative that Israel put a premium on civilian protection," Blinken said during a press conference with visiting British Foreign Secretary David Cameron on Thursday.

"There does remain a gap between... the intent to protect civilians and the actual results that we're seeing on the ground."

The United States has also been pushing to get more aid into Gaza.

Biden welcomed Israel's decision to let more fuel in following the breakdown of a truce "but stressed that much more assistance was urgently required across the board," the White House said.

He also called on Hamas to allow the Red Cross access to hostages that the Palestinian militant group still holds.

Biden separately spoke to Jordan's King Abdullah II, as efforts continue to restore the short-lived truce that broke down last week, the White House said.

The two leaders agreed to work for a "durable and sustainable peace in the Middle East to include the establishment of a Palestinian state," it said.