The US on Saturday deployed a second aircraft carrier "to deter hostile actions against Israel" while President Joe Biden pushed for the protection of civilians amid the American ally's siege and bombardment of Gaza.

The presence of the USS Eisenhower and its affiliated warships in the eastern Mediterranean signals Washington's "ironclad commitment to Israel's security and our resolve to deter any state or non-state actor seeking to escalate this war," Secretary of Defense Lloyd Austin said in a statement.

The Eisenhower joins the USS Ford carrier strike group which arrived earlier in the week "as part of our effort to deter hostile actions against Israel or any efforts toward widening this war following Hamas's attack," Austin said.

The powerful show of support came as Israel appeared poised for a ground offensive against Hamas militants in Gaza.

More than one million people in the northern part of the crowded enclave have been ordered to flee ahead of the expected assault, an exodus that aid groups said would set off a humanitarian disaster.

Israel has also cut off food, water and electricity supplies to Gaza's 2.4 million people.

Biden spoke on the phone Saturday with Israeli Prime Minister Benjamin Netanyahu and "affirmed his support for all efforts to protect civilians," the White House said in a statement, which did not specifically mention Gaza.

"President Biden discussed with Prime Minister Netanyahu US coordination with the United Nations, Egypt, Jordan, Israel, and others in the region to ensure innocent civilians have access to water, food and medical care," the White House said.

Biden also spoke with Palestinian Authority leader Mahmud Abbas for the first time since hostilities broke out a week ago and "condemned Hamas' brutal attack on Israel."

"Hamas does not stand for the Palestinian people's right to dignity and self-determination," Biden told Abbas, according to a White House statement.

Biden in the call also pledged "full support" to the Palestinian Authority in its efforts to bring humanitarian assistance to Palestinians, "particularly in Gaza," the statement said.

A week of deadly Israeli salvos was sparked by a Hamas raid which saw fighters break through the heavily fortified border between the Gaza Strip and Israel and gun down, stab and burn to death more than 1,300 people.

In Gaza, health officials said Israel's response had killed more than 2,200 people. As on the Israeli side, most of them were civilians.

Austin also stressed the protection of civilians in a call with Israeli counterpart Yoav Gallant.

"He discussed the importance of adhering to the law of war, including civilian protection obligations, and addressing the worsening humanitarian crisis in Gaza while Israel continues its operations to restore security," the Pentagon said in a statement.