Israeli troops are preparing for a ground assault on the Hamas-controlled Gaza Strip as the country hit back for an unprecedented assault on its territory, and Iran warned of "far-reaching consequences" if Israel's bombardment was not stopped.
Israel has vowed to annihilate the militant group Hamas in retaliation for a rampage by its fighters in Israeli towns eight days ago in which its militants shot men, women and children and seized hostages in the worst attack on civilians in the country's history.
Some 1300 people were killed in the unexpected onslaught, which shook the country with horrifying mobile phone video footage and reports from medical and emergency services of atrocities in the overrun towns and kibbutzes.
Israel responded by subjecting Gaza to the most intense bombardment it has ever seen, putting the small enclave, home to 2.3 million Palestinians, under total siege and destroying much of its infrastructure.
The expected ground assault had not begun by the early hours of Sunday.
US Secretary of State Antony Blinken began a meeting with Saudi Crown Prince Mohammed bin Salman in Riyadh soon after 7.30am, a US official said, as he works with regional allies to prevent the war from spiralling into a bigger conflict, and help win release of the hostages.
Gaza authorities said more than 2300 people had been killed, a quarter of them children, and nearly 10,000 wounded. Rescue workers searched desperately for survivors of nighttime air raids. One million people had reportedly left their homes.
Israeli Prime Minister Benjamin Netanyahu's government also told the militant group Hezbollah, which neighbours Israel to the north, not to start a war on a second front, threatening the "destruction of Lebanon" if it did.
On Sunday, senior Israeli official Joshua Zarka accused Iran of trying to open such a second front by deploying weapons in or through Syria, in a response to a post on social media platform X that posited such a scenario.
Iran's mission to the United Nations warned late on Saturday that if Israel's "war crimes and genocide" were not halted immediately, "the situation could spiral out of control" and have far-reaching consequences.
Hamas and Hezbollah are backed by Iran.
Hamas leader Ismail Haniyeh, meeting Iran's foreign minister on Saturday in Qatar, discussed the Palestinian group's attack in Israel "and agreed to continue co-operation" to achieve the group's goals, Hamas said in a statement.
The Israeli military said that in an air strike in Khan Younis it killed a commander of Hamas' elite Nukhba Force who led the October 7 attack on the two Israeli border villages of Nirim and Nir Oz.
US President Joe Biden and other world leaders warned against any country broadening the conflict. International organisations and aid groups urged calm and pressed Israel to allow humanitarian assistance to get through.
In New York, Russia asked the UN Security Council to vote on Monday on a draft resolution on the Israel-Hamas conflict that calls for a humanitarian ceasefire and condemns violence against civilians and all acts of terrorism.
Biden called Netanyahu on Saturday and, while reiterating "unwavering" support for Israel, discussed international co-ordination to ensure innocent civilians have access to water, food and medical care.
Biden also spoke with Palestinian President Mahmoud Abbas, who stressed the urgent need to allow humanitarian aid corridors in Gaza.
The US Department of Defense said the Eisenhower aircraft carrier strike group would start moving towards the eastern Mediterranean to join another carrier strike group already there.
Defense Secretary Lloyd Austin said it was "part of our effort to deter hostile actions against Israel or any efforts toward widening this war following Hamas's attack on Israel".
On Friday, the Israeli military told residents of the northern half of the Gaza Strip, which includes the enclave's biggest settlement, Gaza City, to move south immediately.
On Saturday, it said it would guarantee the safety of Palestinians fleeing on two main roads until 4pm. Troops were massing as the deadline passed.
Hamas told people not to leave, saying roads out were unsafe. It said dozens of people had been killed in strikes on cars and trucks carrying refugees on Friday. Reuters could not independently verify this claim.
