(Bloomberg) -- President Joe Biden has promised unconditional support for Israel as it gears up for a ground war in the Gaza Strip. But his administration is worried that the Israeli government isn’t ready for the fallout from the massive invasion that could come at any hour.

People familiar with the Biden administration’s stance say the White House fears that Israel doesn’t have a plan for what comes next for Gaza after an invasion, and is pressing them to think beyond the immediate goal of eradicating Hamas. They asked not to be identified discussing private deliberations. 

The people said Biden’s team has also voiced anxiety about Israel’s demand that residents evacuate northern Gaza in 24 hours, a deadline that both the EU and UN say is unrealistic. Soon after Israel made the demand, National Security Council spokesman John Kirby acknowledged an evacuation in Gaza would be “a tall order.”

The desire to support Israel versus the fear about what might come next underscores the delicate balancing act Biden faces. A punishing campaign in Gaza and no clear endpoint risks fanning Israel’s worst crisis in 50 years in to a regional conflagration the US and its allies would struggle to contain.

For the time being, Biden and his team have sought to show unflinching support given the scale of the horror from last weekend’s attack by Hamas, which killed 1,200 Israelis and saw dozens taken hostage. 

Israeli officials have called the attack their 9/11 and some, such as President Isaac Herzog, have rejected the notion that Palestinian civilians could be innocent. “They could have fought against that evil regime which took over Gaza in a coup d’etat,” he said. More than 1,500 Palestinians have been killed in Israeli strikes. 

Biden aides have steered clear of publicly questioning Israel’s strategy in the conflict against Hamas, which has been designated a terrorist group by the US and the EU. But they’ve also been wary. On Friday afternoon, Biden said people shouldn’t “lose sight of the fact that the overwhelming majority of Palestinians had nothing to do with Hamas.”

Secretary of State Antony Blinken is on mission through the region — he visited four countries on Thursday — as the US looks to keep the war from spreading and seek help winning the release of the hostages. While Blinken has urged some caution by Israel, his focus has been to ask other nations to do what they can to make sure the violence doesn’t spread.

“They need a strategic plan for Gaza and it’s obvious that the plan that they’ve been executing, essentially over the last several years hasn’t worked,” said Seth Moulton, a Massachusetts Democrat and member of the House Armed Services Committee, who served four tours as a Marine in Iraq. Israel needs a “long-term strategy for Gaza that will be more effective than whatever they’ve been doing for the last 15 years,” he said. 

The fluid situation on the ground underscores those risks. To Israel’s north, Hezbollah says it’s ready to act against Israel after its sponsor, Iran, warned that the continued blockade of Gaza could open up a new front in the conflict. Firing across the border has already picked up from both sides.

US officials worry about the humanitarian toll on Gaza, where thousands of civilians crowded streets to flee in the wake of the evacuation order. They’re also focused on the fate of the dozens of hostages and some 500 US citizens still in Gaza. The US is providing Israel with advice on how to recover the hostages, a senior defense official told reporters Thursday. Biden spoke with families of the missing Friday.

“Concern about collective punishment and civilian casualties will loom large as Israeli operations advance to destroy Hamas,” said Kori Schake, director of foreign and defense policy studies at the American Enterprise Institute. Still, she said, “I’d be surprised if the U.S. placed any restrictions on material support to Israel, given the horrific nature of Hamas’ attack.”

Israeli officials have said little about their plans for Gaza, beyond their determination to destroy Hamas. A former top Israeli military officer who remains in close touch with the army, speaking on condition of anonymity, said when the war ends, Israel may set up a temporary military regime and hand Gaza over to an international force, Bloomberg reported. 

Arab governments, like Israel, view Hamas as a threat and an Iranian proxy, even as they and their publics feel sympathy for the plight of the Palestinian people, said Jon Alterman, director of the Middle East program at the Center for Strategic and International Studies. 

“There may be an Arab role in helping legitimize some post-Hamas political order — and even arriving at a post-Hamas political order — that shouldn’t be offensive to the Israelis,” he said.

Heavy Palestinian casualties also risk Israel’s fragile rapprochement with Arab governments across the region, especially the push for Saudi Arabia to normalize ties. Arab officials elsewhere also fear that images of dead civilians could prompt a public backlash, putting pressure on their governments to cool ties with Israel.

A congressional aide said that discussions about Gaza’s future have also quietly begun on the Hill. Congressional leaders are acutely aware that the US invaded Afghanistan in 2001 with the aim of overthrowing the Taliban, but that US troops ended up remaining in the country for 20 years, the person said. 

“It appears that the strategy is to support Israel in eliminating the terrorist enclave on its border and deter others, especially Hezbollah, from joining the fight,” said Richard Fontaine, the chief executive of the Center for a New American Security. “Beyond that - including the big question of who governs Gaza after Hamas - remains a work in progress.”

--With assistance from Roxana Tiron and Iain Marlow.

©2023 Bloomberg L.P.