U.S. 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 U.N. 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.”