Live updates: Follow the latest news on Israel-Gaza
US President Joe Biden stressed the need for Palestinian civilians to be protected and given humanitarian assistance in separate phone calls on Saturday with Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas.
Mr Biden's conversations with the two leaders came as Israel was preparing the final stages of an Israeli offensive in the Gaza strip.
More than one million civilians in the densely populated enclave were given little notice to evacuate, prompting fears that it could lead to a humanitarian crisis.
Twenty-two hospitals were among those given the evacuation notice. The World Health Organisation said Israel's ultimatum “could be tantamount to a death sentence” for those being treated.
Food, water and fuel supplies have all been cut off to Gaza. The US said it is working with regional partners to establish a humanitarian corridor that would bring relief supplies to the 2.4 million civilians who inhabit the Gaza strip.
“President Biden affirmed his support for all efforts to protect civilians,” the White House said in a readout of Mr Biden's call with Mr Netanyahu.
“President Biden discussed with Prime Minister Netanyahu US co-ordination with the United Nations, Egypt, Jordan, Israel, and others in the region to ensure innocent civilians have access to water, food, and medical care.”
In a separate call with Mr Abbas, Mr Biden condemned last week's deadly Hamas attack on Israel and said that “Hamas does not stand for the Palestinian people's right to dignity and self-determination”.
He also offered the Palestinian president “his full support” for continuing efforts to deliver “urgently needed” humanitarian assistance to Palestinian civilians, “particularly in Gaza”, the White House said.
It was his first call with Mr Abbas since the conflict broke out last week.
The Hamas assault left 1,300 Israelis dead.
At a gala in Washington on Saturday night, Mr Biden said the attack was the “worst massacre” of the Jewish people since the Holocaust during the Second World War.
More than 2,200 people have been killed in Gaza and an additional 8,700 wounded since Israel began bombarding the region.
Mr Biden said many of those suffering are “innocent Palestinian families”, many of whom “want nothing to do with Hamas”.
In his calls with Mr Netanyahu and Mr Abbas, Mr Biden also stressed that the conflict must not expand and the need to preserve stability in the region.
The US on Saturday said it is sending an additional aircraft carrier to the eastern Mediterranean to deter any other actors from getting involved in the conflict.
The USS Eisenhower was already scheduled for deployment to the Middle East. It will join the USS Ford strike carrier group.
“The increases to US force Posture signal the US's ironclad commitment to Israel’s security and our resolve to deter any state or non-state actor seeking to escalate this war,” Defence Secretary Lloyd Austin said.