Israel said its ground forces had made a big push into Gaza overnight to attack Hamas targets.

The United States and other countries are urging Israel to delay a full invasion; Gaza is reeling from almost three weeks of Israeli bombing triggered by a mass killing spree in southern Israel by Iranian-backed Hamas, which runs the besieged enclave.

Other Iranian-backed groups have since attacked Israel and U.S. forces elsewhere in the region; Western leaders fear that a ground invasion with a high death toll among Palestinian civilians, who have already been killed in large numbers by Israeli air strikes, could spark a wider war.

U.S. President Joe Biden held a call with Netanyahu, discussing “ongoing efforts to locate and secure the release” of Americans believed held hostage by militants in Gaza, the White House said overnight.

Israel said there were 224 hostages. Hamas has threatened to kill some of those it holds, who include many foreign passport holders, but has freed four since Friday. Gaza began receiving a small amount of aid the following day.

The White House said Biden and Netanyahu also discussed safe passage for other foreigners wishing to leave Gaza, a continuous flow of aid into the narrow coastal strip, and a pathway to permanent peace with the Palestinian people.

“The President reiterated that Israel has every right and responsibility to defend its citizens from terrorism and to do so in a manner consistent with international humanitarian law,” the statement said.

The comments reflect a balancing act over U.S. support for Israel’s actions after Biden was criticised for casting doubt on Palestinian casualty figures.

Netanyahu, who has suggested repeatedly that a ground invasion is imminent, told citizens in an address on Wednesday evening: “I will not elaborate on when, how or how many.”

Israeli army radio said the military had overnight staged its biggest incursion into northern Gaza in the current war against Hamas, which Israel has vowed to eliminate.

The military later released video on X showing armoured vehicles crossing the highly fortified barrier from Israel and blowing up buildings “in preparation for the next stages of combat”.

“Tanks and infantry struck numerous terrorist cells, infrastructure and anti-tank missile launch posts,” it said.

Palestinians in Gaza said Israeli air strikes had pounded the territory again overnight and people living in central Gaza, near the Bureij refugee camp and east of Qarara village, reported intensive tank shelling all night.